He is going to do far more damage to himself by setting around pouting. It is good for a person to be out making himself useful. Speaking from experience if he wants to do something there are ways to do it.
He needs to start out slow and as he learns to work around his limitations and his confidence increases he is going to be much happier and healthier.
I'll second this! After my lung surgery I felt like I couldn't do anything so I ended up sitting around for quite a while and ended up getting up to 286 lbs. Finially decided that being fat was not what I liked and started loosing the weight and I started getting a life back. Fast forward to retiring and the wife let me sit around for about 2 months then she told me find something I want to do. So I started working on small engines and love it.