To give you my smaller level example, it became obvious 4 years ago that my DH could no longer maintain our house and we couldn't afford to live there if he didn't, even if we could find tradespeople to trust, which we couldn't.
I talked and talked about downsizing and he simply refused to engage, until one day, and I can still picture where we were on a walk when it happened, I turned to him and said "Am I house hunting for one house, or two? " and he finally got the message that continuing to live with me in the existing place was not going to happen.
Unfortunately moving after 33 years gave him a full on mental breakdown, but that another story.
They usually don't like change, ASD people. Your DH sounds as though he is trying to get back to something he thinks he knows. Is there an underlying reason why he's looking for that security blanket?