From what you've posted, neither of you are in a position to be anything other than friends.
This is his journey and as he is seeing a therapist, then he is likely getting the help he needs.
IMHO, be his friend, at best. That's all you can do. Support him in his journey as you would support any friend, and do not do any of his work for him. No one learns to fish if we give them their fish.
