ES is right on the money. In Ohio, we have ombudsmen, and they work in a similar way. Also, most larger counties have aging agencies. I think a quick search on the web would reveal something helpful.

You are in an awkward place, though, aren't you? I would imagine you don't want to jeopardize a friendship, and may not want to overstep your boundaries. Maybe there is another independent person you could talk to? What about another sibling? If all else fails, you can place an anynomous (I can't spell tonight) call to the public agecny that deals with the aging.

Good luck.