Newborn coming soon, MIL struggles and mental health - advice please!

I’m currently 34 weeks pregnant with a 2 year old as well. I’m panicking a little as the plan I had for third/fourth trimester has fallen through. My MIL agreed to help me during this time as my husband was struggling a lot with his mental health due to a few things (mainly due to big life changes with moving abroad and back and our toddler not sleeping well at night). My husband confessed to her that he’s been depressed etc but she’s made some selfish decisions (long holidays, spending my heavily pregnant months with other family abroad). She isn’t coming back until I’m full term. Now I can handle looking after my toddler whilst heavily pregnant. But I’m worried about fourth trimester and having no help OR having her help and suffering with my mental health massively. Being around her really messes with my own head. There’s a lot of manipulation and false sense of care from her that angers me. But on the other hand, if I say no to the help she is offering then I feel like I’m depriving my toddler of some 1:1 care from a family member who can feed him, prepare his food and play with him during the fourth trimester. Furthermore, it takes some pressure off my husband and my dad who are my primary sources of support, my “village”. But my son deserves a mum who is mentally stable and I’m not sure that’s possible with postpartum hormones and anger towards my MIL. (There have been a lot more issues that I haven’t outlined here). I feel like the selfless thing for me to do is just suck it up and accept whatever help she offers for the sake of my husband, dad and son. But I also can’t stand the thought of being around her during my vulnerable time. I guess I just want to see what others would do in this situation as my head feels scrambled