Monster in law

How do you deal with a mil that's more like a monster? She told me when I was pregnant that I needed to loose weight. She treats me like I am the worst for her son. I am a stay at home mom and I do everything for him.

She tells me what I need to cook for him and she also has told me I'm not a good enough mother in front of our children. She acts like she is married to him. She asks for money weekly and manipulates him so bad. I've tried to kindly bring up this issue for the past 5 years we've been together. He just gets super defensive about it and says that's his mom. He even has his mom as his death beneficiary because he wants to leave his mom "better off". When we first got together he used to pay her mortgage and all her Bill's. (He doesnt now but still sends her money)

She also must drops her 17 year old son here with us and goes missing for DAYS. she turns her phone off and leaves us with him. She is so irresponsible and I just dont trust her AT ALL. I really dont like her or the way she treats me in front of my kids.

My husband just says that I need to work it out with her, but I am a very passive aggressive person and let people talk to me like that and not stand up for myself. I don't want to be rude and tell her off. But I have blocked her from my fb and my phone.