During visits to a friend she is always rude, disrespectful and demeaning to her elderly mother. The mother was living in her own house with her other two daughters (one of whom was extremely abusive to her and the third sister). The situation was so bad that the mother called my friend talking about suicide. My friend moved her mother to the city where we live with the understanding that the mother could live with her in my friend's house by my friend's rules. My friend encouraged me to be friends with her mother and so I have been witness to many incidents such as the one I mentioned earlier. Sometimes I will say something to my friend, the daugher, other times not, as my observations are not well received. The mother and I have spoken about how her daughter treats her. She is deeply upset by it. I provide emotional support when I can but feel it is not enough. She doesn't want to speak to anyone else about the situation but I know she is depressed due to her daughter's behaviour towards her. I believe this treatment is emotional abuse. When I spoke to my own daughter about it, she disagreed with me.
How do others handle situations like this? I would appreciate any information or advice offered.