<human>: Give me the gist of the text in a nutshell

Reddit, My sister in law is about to lose her house. She went a few months without work. During this time, instead of getting the alimony/child-support she should have gotten from her ex-husband, he decided to pay her mortgage instead. He is on the deed(?) but not the title. Fast forward a few months and she has received notice from his attorney about her paying him back or else they will seize her home. The way I read it, he did not pay her the money he was supposed to, so he could pay that mortgage and seize the house. I am going to direct her to someone ( attorney general, housing authority, police) tomorrow, but wanted to get an idea if this sounds right. Is he committing fraud by not giving her the money she was due, and presumably would have used to make the house payment, and then making the payment himself to have a financial interest in the house for leverage?
<bot>: sister in laws ex husband stopped paying alimony and instead paid on her mortgage. Now he is trying to take her house away. Is it fraud?