Agree with KIA on all counts on this.
Also assuming he's a Singaporean local, not to forget spouse's career and loss of income. And then when he returns to Singapore for good, his kids may have trouble fitting back into local school system, so he'd have to pay for premium schooling from his own pocket. Or,maybe the guy had no urge/incentive to move, so when the HH approached him, he just held out for a high figure that would make it worthwhile. Goodness knows what quality of conversation that headhunter actually had with the guy.
Don't know about now, but ten years back and earlier, companies would generally find it pretty hard to lure married Singaporeans overseas because they and their families were too well settled into the local system and felt they'd be paying a very high price back home to leave it.