If i went out right now and got a girl pregnant with no intention of doing so. I would want her to get an abortion, i would REALLY want her to get one, and i would ask her, beg her. However, if she makes a concrete decision to have it, i would be there for it and her.
It's a bit unfair on both of you if you decide to have it, abortion is not a bad thing as long as it is done before the age of viability (about 20 weeks).
It will force him to grow up fast, eliminate the pleasures of having a mostly resonsibility-free teenage life. It would fuck his parents up. It would fuck him up financially. And it will eventually fuck you up.