Hi! I'll be glad to help you with this issue.
First, let me say I can imagine how distressing this situation must be for you. You are clearly a loving and caring parent. I truly applaud you for your patience and efforts with your son. I've worked with kids and parents in anxiety and night terror issues and I know how frustrating it can be. He's fortunate to have you there for him.
From what you relate, we are looking at a child with a normal developmental history as well as behavioral history till this onset of fears and anxiety at age 10. I once worked with a family where the child saw a movie called Beetlejuice at a friend's house and was traumatized for years until they sought therapy. They weren't as supportive as you are so I'm more confident in your case you'll be able to do this with the techniques below. We worked on methods like the one that I'm recommending you do here with your son.
This is a classic Behavioral technique: He's now in your room and feeling your closeness to soothe himself. I want you to start having a sweatshirt that the main comforting parent wears or a blanket that you have or start having on your bed. It needs to be not your favorite. You'll see why.
You wear that sweatshirt or use that blanket each night for the next 6 nights or so. Then for a few nights you give him the blanket or shirt when he goes to sleep and tell him that it represents both of your love for him. In the morning you take the blanket or shirt and put it back on your bed.
After that, you move his cot to his room. And when he wants to come into your bedroom, you tell him how much you love him, how he's your precious son. You repeat it. You then tell him that it's not healthy as he knows for him to sleep in your room, but that doesn't mean you don't love him. And you want him to know how close you are to him so here's the sweatshirt/blanket that you want him to have next to him or under his pillow that will comfort him and help him know that he's safe. That he's loved. You repeat this whole speech. All in loving comforting tones. And then you do NOT give in. Again, you do NOT give in. You just repeat that the sweatshirt/blanket will help him know how much you love him and that he is safe and that you are all protected.
This is the behavioral program. You have just learned the basic technique of Cognitive Behavioral Therapy (CBT). So make sure to not give in. Remember, you are doing a lot of loving and soothing talk throughout this 2-3 week process. Kids, unless there's an underlying problem, respond to symbolic placement of love and rituals. So be warm and a little theatrical about it.
If this doesn't work after your best efforts, then you need to consider taking him to a psychologist or psychotherapist for help with this. Ask at this school for a highly regarded child therapist. Or ask his pediatrician for a referral.
Okay, I wish you the very best!
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