Starting my 5year old son shooting

My 5 year old son, Stephen, started shooting a .22 Davy Crickett rifle with a 4 power simmons scope. last year. I let him shoot the Aquilla ammo, just primer and bullet. Very quiet and safe. I started him out on paper then went to gallon jugs. Progressed to 2 liter bottles and then coke cans at 15 yards. This Christmas I am giving him the Daisy breakable targets. They look like a flat clay pigeon and are biodegradable. I also plan on using balloons with his pellet rifle and .22. I had planned on starting him with the peep sights but could not explain to him the proper sight picture. I used the Burris Varminteer game on the Sierra reloading disk to get him used to the sight picture through a scope. If anybody has an idea on how to teach him to use PEEP sights or open sights I would appreciate the advice. Hope to start him squirrel hunting in a couple of years. We also spend a lot of time on gun handling and safe behavior while shooting on the range.