Hi HopinAndPrayin Welcome to bpdfamily.
My ask is simple - if you have in-laws who have not been supportive/sabotaging, have you involved them in your SO's care? How has it gone?
While I don't have personal experience to the specific question you are asking, I can appreciate how frustrating it must be for you and it sounds like your father-in-law's "help" hasn't helped much up to this point On the other hand, I would imagine your husband could use the support of his family and if it's he who is involving his father, I'm not sure it's a battle worth fighting; blood is pretty thick.
Would it be possible for you to not offer up information to FIL and leave it to your husband to include him in the way he chooses?
I am completely burned out at this point
Understandably so
What does it mean to take care of yourself? Be especially good to yourself, HopinAndPrayin