His frustration is one of the reasons I would never consider the Hammer Dulcimer. I had a hard time not making the damn thing into kendling a few times. I would not be in charge of his occupational therapy. I let the professionals work with him on that. They know how to keep it fun, when it stops being fun, and how to use the limited time best.What actually impresses me, is his enjoyment of Blue grass and folk music. Kinda a blessing and a curse, while I like the music you can only hear "Go, Move, Shift" about 50 times in a row before the adult mind starts to implode. Actually, while looking for music for my son, I've found quite a bit of more music for myself.
Right now he likes playing with the penny whistles, Grandpa's Guitar (until he gouged the wood of his twelve string), and the auto-harp. I've debated trying to find a cheep autoharp but he loves his guitars more than anything. Maybe a cheap mandolin, or Uke would be better for his little self...