history: My sister in law irritates me to no end.  She lives with my mother in law and cannot take care of her kids at all.  My MIL basically raises them, feeds them, houses them, clothes them, etc. My sister in law irritates me to no end.  I wish my husband would talk to her_comma_ but in their family the rule of law is "don't make waves".  It's ridiculous.
current: I'm sorry to hear that, hopefully she naturally mellows out.
next: No, I don't think so.  She's 45 and cannot raise her kids.  She lives with my mother in law, and my MIL houses them, feeds them, clothes them, basically raises them, while my sister in law takes no responsibility.