In Law help!!!!

I’m so frustrated!!!! My c-section is scheduled for the 21st. My hubs and I live across the country from my in-laws. The in-laws want to come over right after my son is born. I had communicated with my mother and father in law they were welcome to come the day he is scheduled to be born. They were going to stay a few days. I had my husband communicate to his sister, she was welcome to come after for a weekend in early September. His sister doesn’t like me and was highly disrespectful to me during her last stay here, so I am only comfortable with her here just a small handful of days. Well we got contacted today that they were wanting to come all together the weekend after the 28th. They also said they wanted to bring my niece (who is 3) and all four of them were going to stay in our house. I am infuriated! Thankfully my husband told them he was going to talk to me before scheduling them to come, however I am infuriated because we told them we did not want them coming all at the same time also they were informed individually of when we were fine with them coming. I don’t have a good relationship with my in-laws and I know my husband is struggling with them. He is doing his best to accommodate for me because I’ll be going through more stress and pain than him having recover from a major surgery. I’m struggling to draw a boundary. I want to please my husband and have them come, but at the same time, I can’t stand my in-laws and they don’t like me. They are very controlling and I don’t know where a good set of dates for them to come would be. Not to mention, I’ll loose my shit if they try to change them again. Please help me 😥