I caution you against diagnosing people. Diagnosing ASD isn’t easy so just because he acts off or has trouble communicating it doesn’t mean it’s that. If he doesn’t have proper diagnosis, I’d stop saying he has ASD.

Also usually what you see is what you get, if he was previously more commited and spent more time with you but later decided he doesn’t want more commitment and now is going out a lot wuth his friends without you, perhaps he feels something is missing in a relationship and he gives you heads up that it’s not going anywhere.

Future was on his radar and now it’s not. Whatever is the reason. Honestly I’d move on. It doesn’t sound like there is much of a future here. He might not be a man for yiu