My nephew is starting to paint..my sister asked me for advice.

Here is my advice..Hide his brushes and paints and give a medical textbook. Art is hell and war. The thing with art is if you give up and do something you hate then you are more miserable than scrooge in a Christmas carol. There is no way out of the art maze. I dont know how to quit so that was never a choice. I cannot quit art anymore than a stupid person can stop being stupid.