It is hard to describe. But you're right, it is a great thing.
Good luck, you will really have a great time. I can tell you also that my Dad and I started flying 25 years ago. Until I was 16 he and I spent every weekend flying that the weather would allow.
To this day, I have very fond memories of those days. You're son will as well.
Pace yourself, this hobby can eat you alive money wise if your not careful. Make sure that once you decide to explore something its what you really want. There is nothing worse than starting down a path, investing a bunch and then finding out you really wish you had done something else. Been there done that.
I started again a year ago after all this time and got right into glow. That was ok, then went to warbirds, fun, cool, I like them, but they are a lot of tinkering. So I half slid have was carried into gliders and have had the best time yet. If you go to the gliders section and look up my post on the Thermic 2.5m you will see the latest including some pics. Hunting thermals is a great way to spend an afternoon. Teaches patience, is hassle free, and to me is the most relaxing thing I have done in years.

Killer head therapy.

Again, good luck and have fun.

Tom