For what it's worth, I had a similar chance when I was younger and had no children and I passed it up. It is one of my deepest regrets.
If you're young and flexible (no children, not married, no aging parents to care for etc) I'd go for it.
I am young and without any flexible. So moving is not really a problem.
I wonder how can I make my case stronger or ask him to put down more on the table besides just "maybe".