He is good at remembering numbers.
He can tell you whether a box of cereal is more or less than it used to be, which completely eludes me unless the price has, like, quadrupled. Even I can tell that cereal should not be $12 per box.
He can also look at a metric ton of car listings on Craigslist, look up some blue book values, and within 15 minutes have developed a classification scheme in his head that allows him to look at any given car listing from that point forward and know instantly where it lies on the spectrum from fabulous deal to total ripoff.
If anything ever happens to this man, I will have to continue driving the same car for the rest of my life, so I hope I like the one we get this time.