My mother is 75 and I will be 49 not only does she treat me like a 15 year old and constantly calls me to tell me what to do (I have a 30 year old and 2 grandkids) but she constantly gossips between my siblings and other family members about mine and everybody else business even if it's not true. When visiting her home town a couple of weeks ago for church homecoming half the church which were family members didn't even talk to her. The things that she say,are a lot of time not true and simply painful. I hate upsetting her when I tell her to stop but what to you do? Also, she can just be flat out rude when she talks to me. I getting fed up!!!!
Has she always been this way? If not, I'd question what is causing her behavior. It could signal some problem. But, if not, I wouldn't pretend that everything is fine and I wouldn't tolerate it.
I see from your profile that your Mom lives in Independent Living, so she is probably the town crier. Where my Dad lives, these ladies are quite the busy buddies.
Mom needs a hobby to keep herself busy so she can talk about the hobby more then the family/town.