I think that first of all, you should take this up with the teacher, and if you get no satisfactory response, escalate it to the Head of the School. They have a duty to deal with it. Ask the school management exactly what they are going do about it -in detail - and when they are going to do it. They may ask you for time to consider their best options, and that's fine but tell them you expect an answer within, let's say, 72 hours. That puts them on the spot and makes them commit to action.
Explain to your son, too, how proud you are of him for having stood up for himself, especially in the face of being left alone by his classmates. Make sure he understand that in these situations HE is the winner, not the bully who tried - and failed - to make him do something which he did
not want to do. You might mention too that the others who went along with the bully probably did so because they are scared of him, even if they will not admit it.
You will, I am sure, find this website useful: http://www.loveourchildrenusa.org/bullying.php
You might also like to let your son use this tool to build up hes self confidence:
This Bill of Rights was one of the tools used by Virginia Satir, a well-known family therapist. Containing some really basic psychological rights belonging to every person, it really helps to identify and deal with areas in which we have problems.
Read the statements. Note down
any immediate thoughts or feelings that come to you and discuss with your therapist.
Look at yourself in a mirror and read it out loud to yourself. Listen to your voice grow in strength and volume so that you can really start to feel it inside. In the beginning, you may feel silly or embarrassed. You may hear the inner voice say, "That's not the truth". Just hang in there and keep doing it - you'll notice the change within six weeks, if you do it regularly.
1. I do not have to feel guilty just because someone else does not like what I
do, say, think or feel.
2. It is OK for me to feel angry and to express it in responsible ways.
3. I do not have to assume full responsibility for making decisions, particularly where others share responsibility for making the decisions.
4. I have the right to say "I don't understand" without feeling stupid or guilty.
5. I have the right to say NO.
6. I have the right to say No without feeling guilty.
7. I do not have to apologize or give reasons when I say NO.
8. I have the right to refuse requests which others make of me.
9. I have the right to tell others when I think they are manipulating, conning, or treating me unfairly.
10. I have the right to refuse additional responsibilities without feeling guilty.
11. I have a right to tell others when their behaviour annoys me.
12. I do not have to compromise my personal integrity.
13. I have a right to make mistakes and be responsible for them. I have a right to be wrong.
14. I do not have to be liked, admired, or respected by everyone for everything I do.
Best wishes, NormanM