Dmax, I feel for you. I have two sons and I dreaded the years they were aged between 16 and 25. That is the period in a young man's life that he is most likely to come to grief as a result of something foolish he or one of his friends has done. What can I say? On the one hand a parent - fathers do this better than mothers, I think - has to stand aside and allow their child to learn by making mistakes. But when the risks are too high and the possible/probable consequences too severe, it is the parent's duty to step in, even at the risk of estranging a relative or temporarily messing up the relationship with the loved son (or daughter). As a trial lawyer who has done 40 years of, amongst others, personal injury cases, I can tell you that there are three types of injuries associated with motorcycle riding in the city: Severe head injury, spinal injury, and loss of limbs, especially the leg on the side of the impact. And it is seldom the motorcyclist's fault.
I have seen too many young men's lives ruined by motorcycle accidents to be comfortable with the notion of an uncle giving my son a motorcycle or helping him to acquire one. I have become so sensitive to the dangers facing young men that I have given both my sons 3-Series BMW's to drive. I know these cars are safe, they're reliable, and they're cool. Above all, they're classy, and the girls (at the age we're talking about), look twice at a man in a good car. Not that that is their sole criterion, but women - and bless them for it - will instinctively always go for the safe option, and a young man in a BMW 3-Series looks like a safe option. Far more so than a boy on a motorcycle.
I'm with you on this. I've always made it clear to my own sons that I want them to be safe and happy, but in that order.