Tess - I am saddened and shocked at your "D"H's abdication of responsibility in this situation and I hope that in the couple of days you are away, he and your DSD do actually start to face up to some of this. I really hope as well that they don't both just ignore it while you are away, on the grounds that nothing needs to be done until you return. I would be suggesting strongly to them both that you expect the boy and his parents to be apprised of the situation before you return - give them both some responsibility here. My heart truly goes out to you in your situation - I really hope that your "D"H mans up very very soon and takes his head out of his arse.
Maryz - just an idea - you could always print out some of this thread for your DD to read. if you C&P it into a word document, you can delete your own comments (although she wouldn't necessarily know they are you except from this post so you can delete mine too :))
In fact, it might be a good thing to archive and keep for all mothers of teenagers - "Read this and see what disruption, distress and outright misery getting pg could cause and to how many people."
My DS is only 2 so it's a long way off for me but I have my own story to tell him as well as a warning.