If your daughters are normal teenage girls, they’ve done most of the things YOU did in high school and maybe even a few you didn’t know about. You know, making out and petting, maybe even more. Possibly more. Probably more.
That’s if they are normal.
But maybe they are, as you insist, abnormal.
Get your head out of the sand.
All teenagers weren’t that way when I was younger and aren’t that way now. Don’t attempt to disparage all of society because of what popular culture demands or whatever raunchy life you may have lead.
I had fun as a teenager but still lived a life of moral decency because of the way my parents raised me. I’m raising my girls (and boys) in a similar fashion. There are no surprises because I know where they are at all times, who they are with and what they are doing.
I don't think he has his head in the sand, and I do believe he knows his daughter better than you can imagine. My sister was the cut of the same cloth. You can suggest otherwise, of course, but you're in no position to know the truth. Truth based on statistics are a poor way to judge in individual cases.