Even if the worst thing they'd do is a grade-school sleepover prank, that doesn't change anything.

[Aside from make him slightly less concerned about her safety, at least, provided she's correct in her assessment that they wouldn't do anything too bad. He'll just not bother addressing the last part, since that would be a whole explanation he doesn't have the energy for at the moment.]

The stress caused by feeling unsafe in the place where you live is just as serious an issue as what might or might not actually happen.