Need help with my “sister in law”

So my brothers ex girlfriend who is very close to my family has a child with my brother. My brother is a dead beat dad that has nothing to do with his kid or the family. She just started dating this guy who has a ex who is pregnant. She says he says no one can know because his ex is crazy. I told her why did it matter if he’s responsible for his kid. She said yeah I know and he is he pays for her appointments (I’m guessing the copay) and that he wanted her to get an abortion and he’d pay for it. I go on to say he doesn’t want his child. She said no not with her. I said shouldn’t be about her it’s about the baby. She says he said her child is enough for him.They’ve been talking on and off for 1 month. I feel like she should know how shady this all is and sad but I don’t know how to explain it. Am I wrong for what I think? Like do other people understand we’re I’m coming from thinking it’s shady and sad? How can you love someone else’s child but care about your own. He also wants them to not be public at all about the relationship. I think he’s still with his “ex” and is just telling her all this stuffs. What do I know though.