Of course, if your son is only interested, please sign up for an interest class to learn painting. If you want or your son wants to learn painting better, or have a goal about painting, such as being a painter, taking an examination of the Academy of Fine Arts, or taking an examination of special students in the future, I suggest going to an outside training class to lay a good foundation, which will be of great help in the future.
Because I also study painting, I just regret that I didn't attend the training class when I was young, which makes it difficult to learn now. Your son is in a particularly favorable period, so let him learn. This helped a lot later.