Please excuse grammer - I'm just that bad.
For context my (32F) partner (32M) and I have been together for 4 years and every mother's day has been spent with his family. I have an older son from a prior relationship and this is the first mother's day that has lined up with my time with him in years. We had a premature baby in February after a complex pregnancy that has only been out of the NICU/SCU for the last month.
Anyways, I discussed with my partner taking the kids and ourselves out for the day for mother's day to spend some much needed quality time as a family for our first special occasion where we can all be together outside of the hospital. Just the four of us.
Unfortunately my MIL is now saying that my partner is scum, that she is disowning him and hopes he has a good life and that he should have planned something special for mother's day that included her because she brought him into the world and he needs to show gratitude to her for that.
I'll be honest I did not think this was a world ending ask but this is now absolutely awful for my partner and I need to know - AITAH?