I just want to cry

My mother is planning my baby shower and it's going horribly!

So I can't ask her not to plan it, she's got stage 4 lung cancer and this is her first grandchild. She isn't happy about us being pregnant. She had a bipolar moment when we told her and got abusive.

She seems to be going out of her way to do things wrong and because she is sick I can't bring myself to tell her she's out of it.

So far, she's ordering 1 party sub from subway, knowing I have extreme food allergies (plus 1 sub for +60 people?!), booked a venue 4 hours away from where his family lives and 3 hours from where my SO and I live, ordered a marble cake that's 100% blue even though we don't know gender yet and half of his family is allergic to chocolate. She wants to do a pot luck instead of having someone else take over that will take care of the food...

So basically I'm going behind her fixing everything, paying for the new venue, food, games, and decor.

I know I should be appreciative but I'm getting so overwhelmed.

It'd be one thing to throw my own, but another to go behind her, fix everything, and then take care of the rest.