My (F32) sister (F31) keeps getting with abusive men, is there anything I can do to better help her see the red flags and react to that?

How do i support my sister to help her break this habit? My sister has only had abusive relationships, she has 2 kids. Since the last relationship broke down, she has been single about a year. She has started dating a guy she used to work with. She keeps telling me about her dates and the stuff he is saying. This guy is a walking red flag, at first she was saying she could see his red flags but kept dating him, now it has switched to her saying I am being really judgemental over a guy I don't know. This is a pattern of behaviour for her. I don't really know what advice I am looking for to be honest. For the last 14 years I have tried to be there for her but I feel really disappointed that she keeps going for the same guys. Last week she told this guy to get lost after he was nasty to her, I was really proud of her, only to find out she had continued the back and forth, he ended up phoning her and did the usual apology and i didn't mean what i said spiel. She has believed him and they are dating again. He is love bombing her big time. I know there is nothing I can do or say to her that is going to help her. It is hard to watch her do this to herself over and over.