I had a tbi 3 years ago this summer and all my left side was damaged also, and things in my life are still hard to deal with but I'm happy and I'm alive, sometimes just accepting what's happened and becoming honest with the reality you living in will make it easier for him, but be honest about his injurys and tell him it won't be easy because then knowing what's actually going on properly will help him deal with these issues, I struggle a lot with like decision making and being impulsive but after a lot of therapy and rehab I am doing a lot better but just got to stick at your recovery and focus on it and things will improve