I've only been reading it for a day, but he's incredibly typical in that he has a wife and then eventually children, but I don't know how much the two of them make. They must be prodigious savers since as you can see in the graph above, the months during the financial collapse, their net worth barely fell. This is by no means impossible if you have a good mix of cash, bonds, index funds, real estate, and a high savings rate.
In addition to monthly net worth posts, he also offers many money savings and investing tips. It's a great read and I encourage you engross yourself in it.