How to handle overly involved family?

My boyfriend and I have decided that I would claim our 1 YO daughter on taxes this year. However, his family is doing his taxes and his grandma has decided to interject herself. To the point she’s told me she’s disregarding my boyfriend’s opinion in the situation when she talks to me. She told me “my options” are to give him either half or all of it, but that ideally they think I should let him claim all of it since he put himself in debt. And that if I claim him, she wants to do my taxes. (Bc that doesn’t sound sketchy at all lol). She has become OBSESSED with the topic to the point that she’s mentioned it while I was in the hospital for preterm labor at 30 weeks, as soon as I got discharged, while my throat was closing up from a medication, and now mentions it every single convo we have. 

She also let me in on a shady “plan” she has that I don’t feel comfortable being a part of. She plans on putting his money into an account he has no access to, bc they want to try to make sure it’s spent how they feel it should be spent, and not telling him until after it’s done.

The only thing is I am bad with confrontation, especially in this situation, as she’s been the one watching my baby as I’ve had a lot of appointments lately.