Key questions:
1) Where? (ok, not as in "exact location", but something generic... are we talking New England? Long Island? Chesapeake Bay? Carolinas? Florida Keys? That's assuming US East Coast. I'm assuming New England due to Lobstermen comment)
2) Rich people & local fishermen... any tensions?
3) What's the island house like? What's the local scene? Like, are there things to do? Or is it mostly dead?
4) What are expenses overall? North of 100K sounds good, but are we talking about a minor or substantial step up?
For me, it sounds worth it. His kids are grown and he has a girlfriend with a flexible schedule. This wouldn't have been brought to our attention if it was a lateral move, or an insignificant step up. Unless there's some kinda island drama that will make this a headache, or the housing on the island is shitty, I'd suggest going for it.