Kawasaki 500 LT is an excellent first bike...,lightweight at 450 lbs, very nimble, able to leave any cruiser behind at the light if he wants to (same engine as the Ninja 500 - parallel twin with a six speed transmission) and easily keeps up with the bigger bikes (I rode mine in company with a Vulcan 900, a Honda 1300 and a Speedy). There are lots of low mileage ones around because people buy them to learn on and then move on to bigger bikes. Only drawback I found was that in the cold weather if you rode for a while and then stopped for a 40 minute coffee, you'd still have to choke it on startup and let it warm up again for a minute because it's not fuel injected. On the plus side, it's water cooled. If he drops it, it's easy to pick up and parts are readily available at a sensible price. Oh, and despite it's light weight, it held the road really well in crosswinds and when passing big trucks.
Another good choice would be a Suzuki S40. A 650 single cylinder, less go than the Kawi 500, but a decent bike to learn on and lots available.
