I would consider a profile like the OMP Katana. This plane will slow down to a crawl without stalling so landings will be easy for a person learning. It is also responsive unlike most trainers. An unresponsive plane makes it difficult for a new pilot to learn what their inputs are really doing to the plane. Just keep the throws way down to start with and the 40 size 3D profiles are some of the easiest planes to fly that can be found. Another bonus, as your nephew grows in his abilities the plane will be able to do what he wants it to do, just start increasing the throws. I learned on a profile and with the buddy-box system it was great. Just a suggestion.