It sounds like the situation early was an example of a deeper concern. Self-esteem is something that is built over time and is something that you must consistently work on with your son.
The first thing I would do is to set goals for your child to achieve. When he is playing piano, tell him that you want to hear how is doing after he has practiced for 15 minutes. This will give him a goal and build independence; if he can't handle 15 minutes, start at 5 and add another minute for each practice until he doesn't need you there anymore. Make sure you tell him this well before he practices, so he can understand the expectation. Set him up to believe that you want to give him time to work on it before you see it. I would stay away from passing judgment on the music when he plays for you and instead ask him how he felt about the piece. I would however praise him for practicing.
"I am very impressed how hard you are working at learning the piano"
Children, just like us, like routine. If your son's schedule changes from day to day, prepare him for the change. Make a schedule that he can keep with him, so he can check it to see where he is supposed to be any given day. Place one on the fridge, allow him to give one to the teacher and one that he can keep himself. If he asks about his schedule, tell him to look at his schedule. Instead of telling him where he is supposed to be, tell him that you will be there to pick him up or be at home when he gets done or who will be there when he is done.
In regards XXXXX XXXXX laughing at him, first recognize that if he is doing something funny, make sure he realizes that is the reaction that he wants. If he is doing something that isn't funny, don't focus on the others reactions, focus on how he felt about what he was doing.
"Mom they laughed at me well I was playing piano"
"How do you think you did?"
"What was your favorite part?"
"I enjoyed the end, you really played strong."
Don't engage the others reactions if they didn't fit the situation, however encourage a positive response from him if it is an appropriate response.
Work on encouraging behavior and independence and not outcome or responses from others. Make sure that your son knows that you will be there and allow him to express his emotions to you, without judgment.
Please continue to ask questions if you need more answered for this question.
Thank you for the detailed answer. How to handle the balance between encouragement and correction?
I totally understand the benefits of "no-correction", just like in school, teachers said if he spells something wrong in his own story book, don't correct it so he will write more and he will find out the right spelling later. It is a good idea of no-correction, with maximize the effect of encouragement.
That said, I find it very hard to practice this principle daily.
Take piano as an example, we switched to another teach when he is older. The 1st teach was focusing on "enjoying the music", so she didn't care about how he play the keyboard. The teacher he has now said he needs to build the right habit of finger movement and sheet music reading.
Then, I realize what my son establish is not the "right" way to read and play music. So I try to enforce him to follow the "new" teacher's method.
Here come the problems.
1. Once my son knows one thing or one way to do something, he would stick to it and does not want to listen to or learn the alternate way, even the new way is correct or better.
2. If someone is trying to show him something that he thinks he already knows, he turns his head away and he won't listen.
3. Most likely, he feels being corrected or people thinks he is wrong when people trying to show him something he thinks he knows. He does not want people to say he's wrong. At the same time, he is often criticizing others a lot, such as saying his younger brother is not right about this or that. Maybe making other people looks bad helps him to balance his own self esteem inside.
4. He does not want to show something to people unless he is 200% sure he can do it. If he thought he was laughed at once for a certain activity, he would never do it again in front of people, when he made a little mistake at the time.
5. I thought he would be perfectionist because of #4 above, and realized later, no, he is not. For most things, he stops practicing after he knows how to do it once although he is far from doing it well.
So, how to handle the balance between encouragement and correction in his case?
Encouragement can keep him going, but we don't want him to keep going the wrong direction and building the wrong habits. Especially he only takes compliment but nothing else, and doesn't want to do it differently - thinking being corrected.
Doing something correctly, i.e. learning the correct way to accomplish something is important. It does take patience on your part to allow the mistakes to happen and then choosing your reaction to the situation.
Make sure that you are allowing him the space to make the mistake and then not jumping on him after it occurs. Appreciating the effort is important, even if you are correcting the behavior. If he is completing a positive activity in a positive way he needs to be recognized for his effort. After that, you can correct the behavior. It is a subtle difference and something you have to be hyper aware of until it becomes natural response.
Your son uses the wrong fingering while playing the piano.
Instead of jumping of the fingering, make a positive comment to start the conversation,
"I see you are working hard"
Then sit and watch for a minute, don't correct the behavior; instead ask,
"I forget, how did the teacher show you to place your fingers. Could you teach me? That looks like you got it, however didn't she say place your pinky a little to the left?"
Empower your son to learn himself and that the process of learning is power in itself. If he needs to learn how to place his fingers on the keyboard. Take a digital photo of the teacher's fingers in the proper position and place it on the piano or allow him to take the photos and work with him on creating a picture book. Don't jump on him to use it, allow the teacher to show him and give him the visual re-enforcement.
Again, if he attempts something in front of others and gets a reaction that he doesn't like, focus on how he felt about it, not on their reaction. Keep redirecting him to how he felt about it, what he did well. Once you have established this behavior/response, then ask what areas didn't he like, or where he wants to improve.
In regards XXXXX XXXXX sheet music, I wouldn't make it a choir, rather a game. Print out different notes and hide them around the house. Print out a scale and place it on the fridge and have an egg hunt style game. Make the process of learning as fun as possible. If he isn't interested in the game at first, encourage with a reward for finding and getting them correct. Remember to set him up for success. If he isn't good at all at reading music, have a copy of a filled out scale on top of the blank one, so he can use it.
The other thing I would encourage is social interaction. Make sure that he has a chance to interact with his peers in low structured activities. Successful social interactions are a huge confidence builder.
I realize that I have focused on the piano lessons as the example, however the same underlying principles apply across the board. The teacher wants him not to worry about spelling because he/she wants your son to enjoy the process of writing (and get out his ideas), once he enjoys the process correcting things is not a threat, it makes something he enjoys better.
Please don't hesitate to continue the conversation if you don't feel I have totally answered your question, I want to make sure that I have helped you with my answer.
Remember that building confidence is a process.
Thank you for all your answers. I like "once he enjoys the process correcting things is not a threat, it makes something he enjoys better." Hopefully, we will get there, if not sooner.