I would normally say don't finance but in his case he can use a small loan to get himself a better car.
At about $15,000 it puts one in a better position to get a good car that's likely 4 years so looking at about 60,000 miles or so. When we're talking about spending under $10,000 on a car we're looking at cars from the mid 2000s and more than likely well over 100,000 miles unless we're going in that Malibu, Camry, Focus lane.
I think if you have top tier credit and won't be in debt over a year a small loan is doable. I just wouldn't recommend financing as a way of life where when one car is paid off it's traded in for another car. 2.6% is a negligible amount.