I'm going to refuse to change my mother-in-law's diaper
Why are you not going to change her diaper?
She's a horrible person. Fuck her.
Even if you don't like her, you need to help your mother-in-law out. It could be considered abuse if you don't and you could face charges.
I don't care.
You should. How would you feel if your family just dumped you? Family need to be there to support each other.