I like a guy in a wheelchair. This in itself is not a problem, because he has had sex before and we are both gay. The problem is his outlook on life. It's very positive, but he says he's not interested in dating anyone. He says he's not lonely, but he doesn't want to rely on outside validation.
I get that, I just hope he'll change his mind. There's always a risk, but closing yourself off to dating means there's no gain. Why should 2 people be kindof lonely when they can form a love with eachother? Is that selfish of me? ... Kindof. Yes, probably.
Love isn't validation, it is love, plain and simple. Look into his eyes and tell him that you really like him, you don't pity him, you find him attractive and would like to go out on a date with him. If he says No, then he just isn't ready for whatever reason, but take a chance, maybe he just doesn't want to be hurt. Hugs!
I agree with CKarma, go for it, life is too short to waste, ask him out and keep asking him out until he goes out with you or you loose interest. Both ways, problem solved.
You did say though that he mentioned he wasn't lonely so maybe he doesn't share your thought of being "sort of lonely". It's best just to express your feelings and get it all out there!