Domestic violence against my brother by his wife

My brother had love marriage in December 2019 .with his girlfriend , they were in relatnship on and off. She called off relationship 2 times and 3rd time she came again and asked for forgiveness like everytime she did. So my brother forgave her and so we did. She doesn't have a good relation with her family also. We are middle class family whereas her family totally depends upon her salary. Before the marriage her behavior was quite good and we all were happy in spite of her temper nature. After marriage her behavior totally changed. She has become very demandable. She expects to complete each nd every wish of her by my brother. She earns more than my brother. Also she doesn't save even a penny. And aslo asks my brother to spend as much amount as possible on her expenses and shopping etc. Which is not possible for him to do everytime. But when he refuses she acts totally like a TV serial actor total drama. Fainting, not eating. Not talking etc until he talks. Every time he says sorry even if it's not his mistake. Every time we tell her not to do so but she doesn't listen to my mother or father. She lives the life of payinguest in our family like people who live paying rent that is how she behaves. My mother doesn't like her cooking (although she doesn't cook well ) , no cleanliness or hygiene While cooking that is why mother cook food which she doesn't like because she always eat that junk food. I guess she never had a family dinner thing at her house with her family. They were living on rent which she used to pay. And I guess she still pays because all All her salary goes in all kind of expenses. And all everytime she asks my brother to pay for something because it's his job as husband ( though she is independent women still my brother Pays for everything) .so it's been 5 month They are having those arguments every other day. Which is really irritating for us. Her behavior has completely changed. Again when we talk to her she acts like fainting, not eating and not talking etc. My brother is literally handling her tantrums mentally. And he has really lost his smile and eating properly. He is not getting enough sleep because every night she keeps eating his mind. I told him to record whatever she talks in the quarrel for safer purpose. One day she asked by mom and dad to come in her bedroom as she wanted to talk and that talk turned into quarrel Betwn them. Where she was just defending herself. And literally was shouting and pointing at my mother. Now the nature of my whole family is kind hearted even whole society knows this. But she just doesn't get this and tries to dominate everyone of us. Her nature is temper grumpy jealousy always shouting and blaming others. This is a love marriage we did all the things by our money not even a single penny from her. Right from dress to her makeup we paid. Now she is literally mentally torchuring my brother every time he said that we did all things for you. What advise can you give please tell me.