I really wish I could give you some sage wisdom here. It sounds like you're feeling the affects of the lack of control? Things had been settled down for a while & now there's a change & that ruffles feathers sometimes even when we think we're prepared for anything.... and the idea of another financial obstacle when I'm out of options makes me insane sometimes.
I think if it were me I might move Plan B up to Plan A.1 & start getting that option figured out just in case.... & let XAH know (eventually) that since he is refusing to comply with providing you the information as per your legal right you are working on other arrangements. Is there anything in your divorce decree that states what will happen when he refuses to comply?
Are you SURE he's being honest with your friend about even HAVING a job? Could he be blowing smoke here & just fabricating a story?
Drinking again? No surprise there, right? Nothing's really changed just like you knew it wouldn't.
FWIW I don't think the sister thing would trigger you AS badly is you weren't feeling off about these developments with your XAH. I think you see the drama there & are already side-stepping as much as you can.
(((((HUGS)))))