Mental Harrassment from mother in law

Since February, my recently widowed MIL is sputing venom against my husband and me. The issue is that she has a greedy and cunny brother and sister who keep on provoking her for smallest of things. I accidently heard her sputting venom against me and confronted her right away. I even have the call recording. And that what irks her that my husband too got to know her reality. Things that are just her false allegations, perspective and suspisions that are fanned to make it appear her truth. Due to this, day and night she keeps on belittling us in every possible way. She thinks that her brother and sister are there because of love. But in actual, they keep on misguiding her to loot her money and jewellry. We have not shifted to a newer place because the house we live in is an ancestral property and my husband has the right to stay there. Secondly, if we abandon her these people can loot the house by just bootlicking her. She is a pensioner and has aaya to take care of her. And we don't take any sort of money for our survival. But mentally it's harrowing to hear being insulted every day. She talks loudly to her siblings and vomits venom one after another. Its so unsettling for me. I have known her toxic habits long ago, it's just now that the son understands her toxicity. What is the legal step for it?