It’s a massive help for parents when they have close family members who willingly help them babysit their kids for free. However, it can happen that slowly, their demands keep increasing and they start taking their family for granted.
That’s what happened with the original poster’s (OP) sister who demanded that she babysit her kids for a whole week while she went vacationing with her husband. Although it was asking a lot from the poster, all hell broke loose when she refused to do it and sparked drama!
More info: Reddit