Advice on befriending someone please.

[keszj]

i love this guy so so much. hes a friend of a friend and i find him to be the most interesting person ever each time i talk to him, and we really get on (from my perspective). i dont care about dating him. but i would like to be friends. the one time i messaged him asking to hang out one on one he said no which was crusbing. he later clarified that he has autism and social anxiety and doesnt like hanging out with people one on one especially people he's not yet friends with. im moving back to the same city as him in september and i really want to become his friend but it seems impossible.