the SP101 is heavy for what it is, not particularly accurate, the one I had was fixed sights which in a word sucked for woods stuff and in my opinion have a funky trigger. The trigger is for sure funky compared to any smith trigger. I owned one for several years and would never buy one again. I don't know about their strength and all that crap which is what everyone uses to justify their boat anchor weight, but not for me. I would find a used Smith and Wesson Model 66 with a 4 inch barrel your boy will be 10 times better off and a hell of a lot more satisfied with the gun.
Weight of a Ruger SP101, 4.2" barrel, .357 - 29.5 oz.
Weight of a Smith & Wesson Model 66, 4.25" barrel, .357 - 36.9 oz.
Which is heavier?
Both have adjustable sights, btw.