Boyfriend exposing his ex wife

Since I've met my boyfriend he has said that his ex wife is a horrid person. That she's a con artist. That she ruined his reputation and tried to ruin his life. He has custody of their son. I know on Facebook she has accused my boyfriend of alienating their son from her. He's 15 and he doesn't really talk to his mom.

It's been brought to my boyfriends attention that his ex wife has been saying that their son died and started a GoFundMe for the funeral. He had told me before that she had lied about their son having leukemia and scamming a bunch of people out of money. Well now she's saying he's dead. My boyfriend has been obliterating her online. I understand telling people that their son is not dead. He has reported the GoFundMe and it's been taken down. But now it's not just that. He is airing every single thing about her online. Some things I don't even think are relevant like she apparently cheated with her 3rd cousin... He's been so angry and i understand and I completely get letting people know they got fooled by her and their kid isn't dead. But he has been bashing her for 3 days and I just don't know what bashing the mother of your child online will accomplish because now it's led to their child bashing her online. I guess I don't understand his end goal. I feel like I should say something but maybe it's not my business and in reality if I had my baby daddy lying to people about my kid having leukemia and then saying they died I feel like I would be pissed and wouldn't know what I would do.