Make sure he buys a rimfire scope, the impulse from a blowback action is different than that of a gas operated centerfire and is hell on them, also the parallax on .22 scopes is set closer than on a centerfire scope. If he doesn't get a rimfire scope he had better keep it cheap, a fine scope will break under a. 22 before a 300 win mag. Doesn't make sense but that's how it is. Almost every brand worth anything has a scope engineered and labeled for rimfire, I would stick to names like Leupold, Burris, Vortex etc. If he wants to go cheap bsa makes a pretty nice "sweet 22" that has a top turret dialed for the 22lr trajectory so all you do is dial your yardage and no holdover, last I knew they ran around $175.
Remember the rules of thumb for scopes apply for rimfire too... Figure 1x power per 100 yards distance (unless mentioned before you're punching paper) and spend AT LEAST as much on your optics as you have in your rifle. This will always pay off.
"A free people ought not only to be armed and disciplined but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government." --George Washington