Makes sense; 70k isn't nearly enough to own/maintain a property. You absolutely need dual incomes and it looks like this guy is single.
Depends on where you live. I know plenty of people that own and maintain property on a single 40k salary.
That totally depends on where you live. It says he lives in Seattle, could be a cheaper suburb. You can afford a house in most places in the US with a $70k salary. Hell, you can get a whole house for under $70k in the midwest.