Sending my good thoughts and prayers for your son. I hope he will be better real soon.
I agree with your thoughts on trampolines, Robin. I watched a TV program about a year ago on the dangers of trampolines. The report stated that trampolines are falsely advertised as being a fun, safe, and recreational type of thing for families to have in their backyards. They interviewed people who had purchased tampolines for their children, thinking that it would be a good thing for everyone to play with. Unfortunately, it turned out, in many cases, to be a disaster due to the frequency of injuries incurred by the use of the trampoline.
They showed through diagrams and computer-generated images just how fractures in the ankle, knee or leg occur when the momentum of your body bouncing up and down on the trampoline goes against the opposite movement of the trampoline going up and down -- often a break or fracture occurs in an instant. I would think there could be a liability problem of people getting hurt on the trampoline on your property, too.
For the amateur person using a trampoline, the TV report suggested extreme caution on the part of the user.