MIL issues- any advice

This happened yesterday: It was horrible. So my severely disabled sister (non verbal ASD) was due attrain station for 11:15 and it was 10:30 and thought oh I got enough time to quickly give him his bottle so he’s all set fo MIL to look after him. When I was feeding him MIL got really upset and I asked her what was wrong. She said that she feels like I make her feel incapable and that she should be doing the feeding. I explained that I wa a just trying to be organised so it’s all ready because I have to concentrate on my sister, as my partner was working was working and mum was very ill. She continued to just say more and more stuff like: -why does she have to wash her hands as all the articles I gave her was for up to 6 months and how she’s clean and tidy etc -why toys shouldn’t be in their cot like teddies etc when they are sleeping as they can wake up and play with them in the morning etc -that she had three children and she knows what she is doing -that he should be going out more than he has been and she was angry that he wasn’t going on walks etc (it snowed recently and last time I took him for a walk wrapped up he was crying and didn’t enjoy it) -that she feels she can’t treat him the same as her other grandkids because she can’t just pick him up and cuddle him she has to ask etc (she tries to take him off from me mid feed or before his nappy change saying he doesn’t need it and that he’s fine playing) -that he should be left to cry in his cot to go to sleep as they do settle -her dislike for contact naps as you don’t get anything done -I did it all on my own so you should be fine -why not put everything in a dishwasher to sterilise? There’s no need for Milton tablets etc -When you worked in nurseries did you wash you hands each time you picked up a child? -why hasn’t he got a pramsuit if it’s cold as he’s growing out of this one (with Christmas etc I just didn’t have time to think) - She was like I got up at 6:30 to help you and come here etc. that you too anxious and why are you too anxious, I need to look into why I’m anxious so much. (I struggle with my mental health and had PTSD recently from losing my first) She has been overbearing when visiting at hers too so she requests for cuddles when he is half way through feeding or stops us from feeding him so he can play with her. She also follows us if we are going into another room to change him or stops us from changing him. She also stops him from going to sleep and he is due for his nap (8 months) so he will sleep on the nighttime. When I was pregnant with him she warned me that if we move too far away (we live 10 mins away) that she won’t look after him. She also said I should get a breast reduction you as soon as possible, whilst I was heavily pregnant because my breasts look disgusting. It made me so uncomfortable I didn’t end up breast feeding my son. My partner feels torn and he just wants everyone to be happy and I’m worried it will affect and break up our family.