Remind him that although he can't avoid people he can control future exposure to idiots by getting the right job. Teenagers think nearly everyone is an idiot and of course sometimes they are right.

I would talk to him about his feelings if you can. Maybe he was very fond of the last girl who go pregnant and is worried about her.

Also is there a ddifferent school option. While this one sounds supportive 3 pregnant 14 year olds in one class sounds excessive.