Welcome to the Quilting Board!

I don't know if this would be of any help, but it possibly could. It is actually a quilt for patients with Alzheimer's, but
maybe making squares with different parts of the quilt for keeping his hands busy.
http://figjamandlimecordial.com/2011...nsory-blanket/
My autistic son is 19 years old. You would not believe what his current fidget item is. Anyway, I think you should try your idea.
My son spent many years with Silly Putty in his hands. It really does help to calm them.
"Every positive thought is a step in the right direction.”
I think it's worth a try. Sure can't hurt and it's very thoughtful of you to think of it. Let us know how it goes!
The loose threads don't make him nervous, the world does and pulling threads is as good a way to deal with it as any. I think you have a good idea. I just wouldn't use so strong a decorative stitch that it won't come undone. That part may be soothing to him.
Hugs to you as you care for him and your family.
Sounds like a great and very thoughtful idea. Good luck - I hope it works.
Ask his teacher or therapist, they probably have taken data about his picking at things and how it effects his anxiety level. As a speech pathologist, I have seen some behaviors that are soothing and some that increase anxiety. Heavy blankets and clothing are often very soothing, so creating a thick quilt might be a great idea. Good Luck.
I think you have come up with a wonderful idea. go for it!
Never look down on anyone, unless you are helping them up.