Agreed, I expect that is what they meant. "Massive debt" implies credit cards, gambling, or at least student loans. A mortgage isn't a massive debt like that because it is against the value of the house that you own. If you want you can just sell your house and be debt-free. You can't do that with credit cards.

I looked into moving to silicon valley for the enormous salaries, and even when you take into account the insane rent you're still taking home more than you would anywhere else in the world. I suspect it is the prospect of a pay cut keeping him there rather than actual massive debts.