If he would want to borrow e-books from the library, Kindle can't do that and probably never will. The Nook can do that as well as the Sony Readers and the Kobo. The Kindle has the new Pearl e-ink display while the Nook's display is still last year's technology. The new Sonys have Pearl plus a brand new touch screen technology that is amazing! The Sony Readers are also the highest quality hardware with the most features other than text-to-speech, which only the Kindle has. Keep in mind that many publishers require that TTS be disabled anyway. The Sonys are also on sale through November 30 at SonyStyle.com, Borders, B&H Foto and others. You might want to check out all of them at a store like Best Buy where you can compare the hardware and display contrast, even if you ultimately buy online. Be aware that if you buy the Nook from B&N, the return period is only 14 days and there is a restocking fee, unlike Best Buy which is 30 days or longer for holiday returns and there is no restocking fee on any reader.
ETA: contrary to the other answerer, Amazon's Kindle format is proprietary but there are other e-bookstores where you can buy content in that format. Also, Amazon, contrary to the other answerer and the clueless Nook demonstrators, B&N can just as easily delete e-books that were sold to them without the copyright holder's permission. So can any e-bookstore delete those from any internet connectible device, even iBooks. I'm not defending Amazon's handling of that the one and only time it happened. They should have checked more thoroughly first but in all fairness, they weren't the only store selling that one book and by law, they had to remove it, just as Barnes would have to if it were to happen again. Barnes didn't sell e-books at the time, or they'd have been in the same situation. But Barnes is trying to make a Nook selling point of this when it's actually turning off customers to hear their inaccurate spiel about the competition, competition which is, in reality, doing a lot more business than Barnes.
I have two Sony Readers, the PRS-350 that was just released and the PRS-900 from last year. I also had a Sony 500 that I used for almost five years with never a problem. I currently have the new Kindle and it's been replaced once and soon to be replaced again because of hardware defects. It really is a rather chintzy thing and I highly recommend that you check it out in-store before you decide.