It's hard to figure out what happened based on your lack of information but tell me if I've got this right:
-flight was delayed
-cabin crew were going to exceed their duty day limitations
-cabin crew didn't want to do this and told captain
-captain overruled them and continued flight?
Is that correct?
If so I'd say the captain should be taken out back and shot. There are limits for a reason. It would be hard for the cabin crew to properly perform their duties if they were asleep. Perhaps a lack of respect for the cabin crew and their responsibilities? I would hope that the captain would be professional enough not to continue a flight if he/she were fatigued.