I have no idea when a young person is ready for receiving kambo treatment. Maybe it's good to find out what in traditional circles this age is, but age does not say everyting cause it's also a cultural things. It's good to be careful on this.
It might help relieve autistic symptoms. Even cure them for a bit, but I'm not sure. This is mostly unexplored territory, so unless you find a healer who's certain and experienced in this light, you're be facing the unknown. No clinical studies or even the slightest indication it may be beneficial. Yet the frog is miraculous and it wouldn't surprise it would be great benefit.
Even if you keep the treatment solely for yourself, it may benefit your son by being able to better understand his needs...
Just my two cents here...