D.B.
This sounds like a situation with a lot of hurt in it. But I think you have to look at the bigger picture. I looked back at your prior questions as well as your profile. You're recently married (2018), you have kids and ex, and stepkids and a husband, problem in-laws (parents and sister-in-law), a job and issues with cooking and getting everything done.
Your marriage is not working. I'm not saying it's not salvageable, but it's not working. You and your husband are not on the same page, there are already discussions of cheating (whether real or rumored, it doesn't matter), and you're more focused on the parens and the sister and the friend.
You and your husband have to hire a qualified babysitter and you have to get into counseling. That's the only way you're going to work out elder care and blended families and drama and terrible communication.
Otherwise, why not divorce and get rid of all this drama? Put your marriage first and let the other stuff wait. But you cannot do this alone - you have so many questions on so many topics, you have got to get a professional involved to help you sort things out.