Originally Posted by Thriftweed Fancy Pants
Doesn't that seem counterproductive? Why would LeChuck show Guybrush a vision of him defeating LeChuck at all?
And that still doesn't explain his dream beforehand.
It's possible that LeChuck didn't expect Guybrush to actually make the doll (After all, each time Guybrush defeats him, it's because LeChuck underestimates Guybrush), and that he put the skeletons there just to reinforce the claim that he is Guybrush's brother. Aftyer all, who would be more likely to have your parents's skeletons: a brother or a total stranger?
IT's also possible that LeChuck planned on having Guybrush think he was defeated, so Guybrush would think LeChuck couldn't harm him anymore and let his guard down and get cursed.
The dream isn't as shortly beforehand as it seems: Guybrush spends 5 days in the crate to LeChuck's fortress, so it would be about a week earlier. As for the contents of the dream: consider that LeChuck had just come back to life and was chasing after Guybrush. He was probably terrified. Maybe his parents died when he was a kid, and he fears going after them. Maybe his parents were still alive and he fears LeChuck may kill them.