OutSmartTheSystem , When I finished reading your first paragraph this is how I felt.
Have you ever heard of a "smooth talking snake oil salesman"?
Is it possible your soon to be ex FIL has smooth talked his customer, conditioned her with , "Oh, no need to bother your kids, I'll do it for you"?
Also, "You know how much your kids love where they live. If you leave me your house, i won't sell it/get rid of it like your kids probably will, I will keep it just as it is to remember you by".
Is it possible when her children call her, she tells them don't worry, I'm fine, ex FIL, takes good care of me...so you don't need to worry. Have a great day kids. Kiss the grandchildren for me. (So maybe The Kids don't feel all that welcomed and that mom has more "feelings" for ex FIL than them, so back off.)
If you are getting divorced...have you found your soon to be ex husband, at all like your FIL?
Does/did your husband love you? Did he want to spend a lot of time with you? Do extra special nice things, just for you, to make you happy? Did he make you feel like you were the most loved person on this earth? Is your husband a chip off the old block...The apple didn't fall far from the tree? Do you trust your husband? Is your husband a snake and so is your father-in-law? Only you can answer these questions.
Please keep us updated OSTS. This is upsetting to me. No one wants to be used.
Does your FIL help out other needy people, or organizations, just out of a good hearted personality, or only those that have a payoff for him?
Just Lois