Don't forget that someone new to the hobby especially someone young will often not have the immediate skill sets needed to repair well. Sometimes an ugly repair still works, so avoid being overly critical of his first attempts at repair. If the repair looks like it will work congratulate him on a job well done, then offer one or two hints that "may make it easier, lighter, more efficient, etc. As long as the repair job is adequate the rest will come with time and a few lessons along the way.