I am not at all sure how to handle this situation with my friend, advice welcomed, please help

Background: I (25f) have a friend P(23f) who is dear to me. She has a lot going on in her life, medically and emotionally, I know she’s being treated or at least was. She somehow ends up in unsavory situations that involve alcohol and drugs, which can be fun but also dangerous. Most recently she was in a mental hospital for a week, also someone “drugged” her (I only say that because I heard different stories) and had a seizure from over consumption while camping and didn’t do anything about it. And even more recently she complained about a guy being too rough which she was very upset about, but then slept with him again and bragged about it. I was very confused.

On to the problem: a month or so ago she became friends with D (30 or so M), when she introduced me to him we got along just fine, he was good to talk to and seemed like a generally good person. That same night a guy C(28M) inserted himself with our group. I wasn’t a fan of him For one reason that night: when P was upset about something that happened, he took her behind the bar and they smashed glass bottles together. I think that’s a very poor way to handle your anger, considering it’s a public space and someone can get hurt. I voiced my opinion, they said they’ll clean it up. A few weeks later we were all hanging out again at D’s apartment and C was there, missing all his teeth, with “broken ribs”, I heard two different stories of how that happened, both from him. D gave me a look, then told me he wasn’t a fan of C, i said neither was I. As the night goes on and we go from bar to bar, I noticed that D was paying for both P and C, I ask him about it and he says that C is homeless and unemployed. I ask why is he out constantly, drinking and also doing drugs instead of trying to find a job and a place to stay? D didn’t know the answer to that. So I asked P, and she said that C is very misunderstood and in a bad place then started crying saying that I have no right to judge him, I tried explaining more that I don’t think it’s a good friendship for her but she kept walking away in tears so I left. Over the next week she was “camping” with C because he’s homeless and it’s giving him a place to stay. That’s when they were binge drinking, had basically orgies with other people and she had a seizure. She told me she cut off D because he insulted C and also tried to take advantage of her when they first met months ago. I didn’t say anything but thought why keep hanging out with him and introduce him us if he actually tried to take advantage of you? At this point I don’t know what to believe, P is still trying to defend C sending me paragraphs about how she’s trying not to judge anyone. I just tried to be civil because she’s somewhat fragile and I don’t want to make a mountain out of a molehill, I just basically told her I wasn’t judging her and my resentment was directed at C, so she shouldn’t make it about her and that it’s ok for people to not like another, she can be friends with whoever she wants, I just don’t want to be around him. D texted me and wanted to get drinks with me and my BF, we hung out for a few hours, had a few drinks and some food and went our separate ways. Today is her birthday, she texted me saying “you actually hung out with someone who took advantage of me. That’s nice.” I haven’t responded yet because I have nothing nice to say about her behavior recently and about the situation as a whole. At this point I think I’m ready to cut ties with P, but we’ve been friends for a few years now so I want to try, I’m just not sure what to do.