Hi - To make an informed recommendation, ask him if he plans to play back prerecorded tapes or tape his own music? Makes a big difference. To simply play back prerecorded tapes, a good Teac will do just fine. If you're recording, a Revox would be great, the sound is far superior to a lesser deck. But there are questions like: 2-track? 4-track? What speeds does he need? What size tape reels - 7 inch? 10 1/2 inch? Reel-to-reels are a lot of fun, but there are many, many different types. Feel free to e-mail me directly, I've owned lots of RTR decks, and will try to help as best I can.
Good Luck, Ed