If he is suffering from depression, giving him fat burners is not the solution. Falling out of shape from any injury or illness is utterly depressing to those who care about his/her physique as well as it is taxing for those close to the victim. If you truly want to be there for him, you need to have a sit down talk and give as much verbal support as possible and offer to be there as a friend 24/7. I'm not trying to be Dr. Phil here, although I do have a degree in psych.
Stress the importance of realistic long term goals and educate him on a couple of supplements that will help him in the long run.
Super Cissus Rx is a newly released product from USP labs that has a better extraction method for an herb that has been proven (in the original Cissus Rx) to heal and relieve pain from damaged joints, tendons, and ligaments, as well as strengthen and build muscle mass.
Anabolic Pump is another product by USP Labs and through trials this compound (P-Insulin) has been effectively used to dramatically change one's physique by partitioning nutrients to skeletal muscle tissue as opposed to fat cells.
Camphibolic is a staple supplement of mine, also by USP Labs and can help one cope with stress, reduce cortisol, and lean out by naturally boosting one's metabolism using Forslean.
These 3 supplements combined should logically give some tremendous physique changes in short time and can continue rebuilding what physique was lost after the accident... and surpass even what was.
I'm not trying to sound like a commercial, but USP puts out some very good, safe, natural compounds that work!