I have to agree with Mary. The only way to stop the rough play is to STOP the rough play!! If you ask your parents NOT to play like that with your cat, might that help?? Cat Dancer is a good toy. Will your cat chase after balls?? I do not think I would exposure your cat to catnip until his behaviour improves! Good luck and please keep us posted!!!
PS: Talk to your vet about Soft Paws!!