One thing is bugging me. When people say that he's young, so now is the time to take risks because he can bounce back. That's just bad logic. Lets say he takes the risk and it fails. Well we all already know that he's going to knock this chick up. So when it fails he's screwed. You don't want a crazy baby's momma in your life, and it's not fair to your kid.
If there was no kid involved... I still wouldn't do it (high school drop out with no job no thanks), but I could see that it's not a horrible risk because it would be easy to break off. With this kid there, she sees him as a guy who can take care of her and her child, so she's going to try to lock him by having another kid. The reason why I wouldn't do it even if there isn't a kid involved is because she'd probably want a kid just to keep the relationship baby. That happens all the time.