Should I tell my partner exactly what I think of his mum?

I told my partner tonight that he shouldn’t always listen to his mother because despite the fact that she is smart is some ways, she doesn’t give the best advice when it comes to relationships. She told him not to respond to a Christmas message from his cousin because she (his mum) is currently not on speaking terms with the cousin. I told him not to get involved in her dramas and that it would be rude to not respond to the message.

Every time I talk to her I just think about this quote - If you ran into an asshole in the morning, you ran into an asshole. If you run into assholes all day, you’re the asshole.

My partners mother is like this. She constantly has terrible things to say about people and is always complaining about other people but she is the problem.

She has a terrible relationship with her daughter and other son, she bitches constantly about all of her coworkers, she says terrible things about policemen and firefighters in the area (she’s a paramedic), she has had allegations of mistreatment made against her by patients which she denies, she has a terrible relationship with most of her siblings, she has even started calling her granddaughter ‘a bitch just like her mother’. She tells her husband to shut up and speaks so rudely to her family. She is demanding and bossy and really difficult to deal with.

So far the only major issue I’ve had with her was her standing on my foot and gripping the back of my hair tightly to demonstrate how to get children to listen (I know. WTF?!?! She’s not going to be looking after my children!) and I told my partner about this. At first I thought she was trying to intimidate me but I’ve since realised that she is just very unaware of socially acceptable behaviour.

I think she likes me but I don’t know what she might be saying behind my back. 🤷‍♀️

My partner values her opinion because she is an academic but I really hate it when he takes her advice.

Should I let him know exactly what I think of her? Or should I 🤐?