Your friend called in a "favor" each time to the banks his dealership always works with. It's a common thing and reserved for high credit score clients. Helps the dealer still make a sale instead of losing out due to financing negotiations. Dealerships work with certain banks and credit unions (many local) and give them so much business that they can call in "favors" for low rates here and there. Use to have family in the business....let me tell you, it's sad/depressing/scary/uncalled for, how many Americans are absolutely terrible with money and/or have terrible credit and no savings. So a lot of the loans these banks give have higher interest rates than their average, so the "favors" are no big deal.
Any dealer who tells you this is not true, either doesn't take part in it, needs to learn it, or needs to develop the local relationships.