Man I so feel you. I'm wondering could my dad and your MIL be related?
My dad has done similar stuff in the past, and worse. I remember when I was 5 my room wasn't clean up to his high standards so he rounded up all of my toys into the back of his truck and took them to the dump, and he made me watch my toys go through the trash compactor. I was in tears.
After that I was afraid to even leave one toy out, when he walked into the room I would haphazardly shove everything into my toy bin and shut the lid. I think that's about the time I got into books, I learned he wouldn't throw out books.
I'm soooo hoping I get this apartment soon, and I'm hoping you get your own place again soon. It's just not easy being an adult child with a family of your own living with your parents.