Now see, my recollection is that he and his kids were eaten by the sea serpents _before_ the Trojans decided to ignore his warning, and in fact the snakes had a lot to do with the decision not to heed the warning:

Laocoon: "Hey! This is suspicious! Lemme thunk my spear into the horse, cause I'm betting it's hollow!"

[Laocoon throws his spear. It strikes with a resounding thud, indicating that the horse is indeed hollow.]

[Sea serpents arrive and eat Laocoon, then boogie off to go eat his kids.]

Other Trojans: "Hmm. I think we better bring this inside."

Okay, Monty, I'll take what's in the box.