I don't see anything here to say he's on the spectrum, he's not routinely cutting people out and can clearly maintain friendships for years.
And I can do it. It's the result of an abusive childhood. I simply force myself not to think about a certain person and situation. I don't do it often but I can walk away from people with relative ease if required and protect myself emotionally, it's a self preservation tactic.
I'm not sure trying to diagnose him with some mental health disorder is really helpful here. Or what benefit it serves.
My opinion would be he is no contact with you Lilly due to guilt and because it's easier for him. It's that simple. With his social circle he probably realised there was no way back.
For the house , He is probably giving you a period of grace to live in the house unbothered and with his financial support , to enable you to have time to move on, so a court cannot say he behaved unreasonably and didn't give you time. In addition it maintains his ownership and prevents repossession.
As said, I do think he will probably look to buy you out as settlement when it comes to it, as you cannot maintain their on your own and It's the only valid financial option he has on the table. Equity is low, he would struggle with getting another mortgage, so taking over the house would be the only sensible option for him whilst giving you a lump sum.
Looking at rhe practicalities of what stunt he will pull next is probably more beneficial, but I'm more action based. You've already got legal advice so, should hopefully be prepared what ever he does, because he will do something, it's really just a question of when.