As yobuck said, they can be practical if your scope fails you for some reason. However, they require you to mount the scope higher than ideal for other reasons. I think they are worth having on a lever gun b/c you normally have to mount the scope pretty high to clear the hammer anyhow.

If it were me, I'd encourage him first to practice "pulling up" and seeing through the scope properly. What I tell my wife and nephews is this:

"Look out the back window and pick a target... keep your eye on the target... now, without taking your eye off the target, pull up the rifle and move the scope into your line of sight... " you should be able to "slide" or "insert" the scope into the line of sight and instantly pick up a good picture in the scope.. Do it 10x then rest. Pick up a while later and do it another 10x and rest. DO that every other day or so for a while and you'll get good at it and feel a whole lot more comforatble handling the gun in general.