Can someone help dosmetic abuse ?

I need help my sister just told me that my brother in law has been abusing her for so long and it breaks my heart because she doesn’t express her self with anyone because she feels alone because she says she has know one to talk to I told her you can talk to me she said i don’t wanna put that weight on you she has just been crying and crying it breaks my heart they have two kids. She says “you don’t know what happens behind doors but he has hit me so many times and has constantly put me down saying thanks to me you have a phone and thanks to me you have this and that” she’s a stay at home mom. I told her she had all my support and we talked. I also went off on my brother in law because never in a million years except that to happen idk what to do what else to tell her? His constantly sayin she won’t make it with two kids and she’s tired of him