Get him stuff that helps the family so he doesn’t feel useless and guilty. That’s number 1. It’s awful to feel like a burden to everyone, and that doesn’t go away no matter what is said to you.
Second, stretch bands to put around limbs and pull. It feels amazing. You don’t realise how little you move and how little muscle you use while subconsciously “nursing” a broken bone.
Something insanely complex that involves both arms to use or solve. It’s just funny as shit. But also, I swear I recover faster.