My brother (18) might have impregnated a girl. What do we do?

As per the topic, my brother had sex with a girl around 4 weeks ago and now the girl has just told him she's pregnant. He's claiming he was careful and didn't think that this could happen. I don't know what to say about that. Now, given the high chance that he might have done it, my obvious reaction is, they are both not ready to be parents. My bro is 18 the lady 17 (she's actually In form 4) and my brother completed high-school last year so yeah, they are not ready to be parents. I am fully pro choice so I asked if the girl is willing to Abort and the response was no, coz she's scared. My brother is telling her he can't provide financially but the lady insists she'll take care of the kid herself. I don't know what to say so I suggested they go to hospital and get professional advice from a doctor but the lady has refused. I'm the only person my brother has shared this with and I really don't know how to help. Kindly advise 🙏