I'm not comfortable with unsupervised teens!?

I was out last night, quite late too. I came home to find the two guest teens asleep, but my 15 and 17 year olds were still awake at 1:30 AM. My husband goes to bed very early, leaving them basically unsupervised from 9 PM till 1:30 AM.

The result is a 15 year old with cold symptoms, again.

They are all basically good kids, but the older one doesn't always get along well with others. We have a dry house, no one smokes, too far from town to get into trouble. I just don't like the repercussions that result from a super late night.

We are in the process of getting a divorce. Amicable. But one of my big complaints has been his inability to handle the kids. He either over reacts or does nothing, usually because he's asleep. I expressed my concern. He has objected to them staying up late, but refuses to see anything wrong with going to sleep and leaving them without supervision.

Opinions?

Once he moves out I can run the house as I see appropriate, but do I gently put my foot down till then?