Is his ex fishy

My boyfriends ex girlfriend messaged me yesterday saying she wanted to warn me that my boyfriend is crazy. That he was really awful to her in the relationship. That he has BPD. That he cheated on her. Basically that my boyfriend was not a good guy. I confronted him and he seemed confused for multiple reasons. He started with none of that is true besides he has BPD which I already knew that. Biggest reason he was confused was because two day prior to this she had messaged him apologizing to HIM for multiple things. One was being a bad girlfriend. The other was lying about her age. They dated when my boyfriend was 17 and she was supposed to be 20. Where they lived age of consent was 18, however minors could consent to sex with someone within 3 years of them. So a 17 year old could consent to sex with a 20 year old which is how old she told him she was. She was actually 25 almost 26 and when he found out he ended the relationship. She was apologizing for how SHE treated him and for lying about her age. Saying she's disgusted with herself for ever dating a minor to begin with. Do you think the things she told me about him have merit? Or is she being two faces?

Edit: I typically try to listen to women when they're warning you on a bad guy. I didn't just dump him. I gave him an opportunity to speak.

Edit2: I know he isn't lying. He showed me her apology. She flat out says she should have never lied about her age or dated him when he was just a teen