False accusations / family harassment

I took care of my mother alone who was suffering from terminal illness for a year. We have been estranged from my brother and have no other family. After my mothers death, my brother has been harassing me for my mother documents such as passport, bank cards etc., when I refused to give me that he started accusing me of false allegations of financial fraud that I used my mother’s money, and that I didn’t look after her. All my relatives know that I’ve taken care of my mother and was handling all her medical and financial matters. nIf my brother was absent from my mothers medical treatment or in no contact with her for years, he’s trying to defame me with these false allegations so other people don’t raise a finger at him. However, all this is really affecting me and my relatives have asked me to ignore his allegations and move on. But I don’t want to, he has no rights to spoil my reputation without any proofs. I want to legally put a stop to this nonsense, I want to know how. Thanks