The best thing to do is to take another lesson at a smaller friendly
hill. The big mountains are machines that have to serve thousands of
customers the cheapest way possible.
Take another lesson, but only with you and your son, when there are 4
people in the group it is hard to get the personal attention. This
costs more but if the other 2 people in the group do not pick up fast
you will be stuck learning at there level. Get the equipent in the
morning, practice getting your balance then try some side slipping,
heel then toe side. Now you are warmed up go to your lesson.
Some tips are to wear knee pads and elbow pads, helmet and bike shorts
with padding. When you catch an edge and land on the knee pads you
will be smiling.

Hope this helps. Some people can pick it up fast while other it takes
a little longer. Good luck and do not give up on the sport!