My DH tends to follow my lead (mostly :) when it comes to decisions like this.
What you might do is have him read about how sleep is so crucial to health. Print off some articles; NY Times did a really good, comprehensive article on sleep and how it's lack affects kids. When kids sleep, their body rests and heals. That is actually when the body releases growth hormone. Lack of sleep is linked to type-2 diabetes, heart attacks, obesity and other problems. Kids who don't get enough sleep are, literally dumber (in the short term) than their well rested counterparts. Dr. Ferber has a lot of good info in his book Solving Sleep Problems (I think that's the title, or it's pretty close).
Maybe sit down with him and share the medical science that shows the adverse effects (which can be lifelong--good sleep habits start now, and will last the child his or her whole life!). Explain to him (show him articles from reliable sources) that tell the average amount of sleep a child at your kids' ages needs every day. Talk to him about how to solve this issue. Enlist his help--Ask him what you can do to help him get the kids settled. For example, maybe calling or text him to remind him, (if that is of help; hopefully he wouldn't see it as nagging). Or setting a timer or an alarm clock for when it's time to go to bed. You could put the TV and lights on a timer.
Or, maybe you can enlist your pediatrician--talk to the pediatrician about the fact that you're concerned about sleep issues, and explain that you're not sure your DH understands why sleep is so crucial.to kids' well being, and then ask if the pediatrician can talk to both of you about it, so you're all the same page. Let him know that the pediatrician can answer questions about sleep & its link to health.
I wish you luck. I can only imagine how frustrating this is... he's not the one who's dealing with crabby, tired kids the next day...