The main web browser for Macs is called Safari, though lots of people install Firefox these days, and some have an old, old version of IE. I'm guessing he's not in the Firefox camp, so it will most likely be Safari. Unless he's had the computer for several years, in which case he might still be using that old version of IE.

And that's about as much help as I can give. If I were sitting right there in front of the computer, I could whiz through what you want to do, but I don't know Macs well enough to talk anyone through it remotely.