Per everyone's advice, I've been keeping my distance from SIL (she from the bottle and denture thread). I've not responded to any of her phone messages and have let DH handle her.
Last week I finally caved and met up with her for lunch. The first thing she started talking about was a new bed. SIL has mobility issues and, within the past few years, has developed bedsores. She is also on Medicare/MediCal, which provides for most of her medical needs. She wants to me to ask DH if he would give her $1000 for a special mattress. I responded that was between herself and DH. The conversation went like this:
SIL: "I really need that bed, but I'm scared to ask (DH). Can't you ask him for me?"
Me: "That's between you and DH. I can't interfere."
SIL: "It has one of those foam mattresses that is good for bedsores. You know how I suffer..."
Me: "I can't interfere. That's between you and DH. You need to ask him yourself."
Repeat ad nauseaum. I cut the visit short and came back immediately after lunch.
I went home and told DH about this, and his first reaction was "CRIVINS!, $1,000!?!" Now he's thinking about it, or at least providing half. I told him I have problems with this because (a) it's the time of year when property tax, car and home insurance, and DMV fees all fall due; (b) he just invested a ton of available cash in the stock market, leaving us with just enough for bills and everything in (a); (c) If she really needs that bed, she should go to her doctor and apply for Medicare/MediCal to pay for it.
Yes, there is a question in all this - how do you shut up someone when the "broken record" method isn't working?