Wow, that is really bad. Not only that your husband thinks it's funny, but his disregard for you, when you've asked him to stop. Seriously, if it was me, I would be very angry with him about this.
Obviously he thinks you are just 'overreacting' or being too picky. So I would call in reinforcements. Have you spoken with your mom about this? How about HIS mom? I don't know any grandmas that would think it was ok for him to sugar the kids up like that, especially before bedtime. Men are creatures of habit and what he doesn't want to hear from you, he may take more seriously from his own mom or all of you.
Also, schedule an appointment with your family doctor. Make your husband go with you. Call the doctor ahead of time and explain the situation with him and let THEM explain to your husband that what he is doing is REALLY bad for his kids!
It's too bad he doesn't take you or what you are telling him seriously. He ought to, and honestly, if it were me, I would bring that issue up with him as well. It sounds like he really does not respect your opinion or the time that you have to spend bringing the kids 'down'.
I don't think you should feel bad AT ALL about ganging up on him about this in any way you can. He brought the situation on himself by acting ignorant and ( sorry!) plain old, bad, inconsiderate behavior! If he had been reasonable in the first place, you wouldn't have had to ask for help with this!
Although it is true that if there are no 'sugary' snacks in the house, he can't serve them, I don't know that you should have to NEVER allow a treat in the house, just because your husband cannot stop himself from giving them to the kids! Who is the adult here, for Pete's sake??
Providing healthy snacks for your kids is great and you should do that anyway, but the issue here is your husband's blatant disregard for his own children's health and his disrespect for what you've asked him to do!
Good luck- stick to your guns here and don't back down! This could become a serious health issue for your kids later, even if your husband just thinks its funny now. I am sure he loves his kids- he just needs to learn that flooding them with sugar all the time is not a good way to show it.