Being an "Aspie" myself,I agree with *Nelliemoser" about your son in law probably having a mental health issue that causes his behaviour.Does your daughter happily live with his routines and idiosyncrasies?Has she ever complained about them or said that she finds it difficult to cope with?She has probably just got used to his ways and accepts them.I would definitely ask her about this if I were you.
His behaviour is probably part of his character make-up and although I understand your irritation,I don't think it is worth rocking the family boat over.I would think twice about moving near to them for the time being though,especially as you have other reasons to stay put.
What made you fall in love with comedy?
What do you miss from back in the day?
What sort of family would you not want to marry into?
"Old fashioned" expressions that young people have never heard.

, but it cleared the air and things have settled into a jokey ... may I ... routine when he is here