Who cares let him just have fun.
well by the sounds of it hes getting very frustrated and not having fun because of washing out on his landings. plus its his dad, can you really tell him to not care about his son getting frustrated over something?
in my opinion, video review is one of the best things to do to help correct your form. something that you might think feels alright could actually be completely off and once you watch yourself most of the time you can see that.