Ombudsmen, is the right person to contact and they can advice you. ( I doubt very much your name would be brought up at all) If they are just laughing and joking about what "the person" did ect. that may not be abuse if they are not doing it in front of her ect. This can sometimes be a big problem with caregivers and they need a break or to get out of the situation. Sometimes what is being said might just seem like abuse as they are making light of it. but - no way should they be talking about her in that way and whats worse is other people hearing it. You can imagine how we would feel.
Maybe the mother has stated she does not want to go into a nursing home and the family feels guilty if they do. (my mom tried that with me b/4 she got so ill and when she was very ill and very mixed up - she would still yell at me " Don't ever put me in one of those homes or I'll.........") LOL Anyway I would sure go ahead and call maybe they need someone to intervine.