Nothing, the kid can't shoot for $hit.
A higher power scope ain't gonna fix that.
By the OP's description it sounded most likely A: He wasn't using a good rest, B: He just had a bad range day, C: The scope mounts are out of whack, D: The scope is junk, E: The gun isn't accurate in the first place, F: Even though he tried 2 types of ammo the gun still didn't like it at all, or G: Any combination of the above.
And if you'll follow some of his other comments, he's shot other rifles with better results. Obviously there was a reason he thought he wasn't shooting well with THIS rig.
If you read what I wrote(I quoted it for to make it easier), you would understand that any of those causes or a combination of any of them could definitely cause a guy to scratch his head and wonder what is going on. I know if I went to the range and started shooting 3" groups at 100 yds(granted with my 30-30 that is about all she will do with open sights, we will call it 6" groups for her) I would be wondering why I wasn't shooting well and start looking for the reason.
I perfectly understand your point of the magnification, but in this case it is a useless argument. Draw a 1" circle on a piece of paper, look downrange through a 4x scope, unless it is a crappy scope, it is more than enough magnification to shoot <6 MOA groups at 50 yds. There appears to either be something mechanically wrong (note C,D,E,F)or he wasn't able to achieve a proper rest or shoot well and didn't properly call his shots(A&B), if stuff was really going wrong read G.
I can't stand when people push high power scopes as "real scopes". I choose a 3-9X because it gives me adequate magnification to reach out and kill a deer/elk at 500 yds, but also provides a wide enough FOV so I can find a target quickly at short range. Plus higher magnification scopes are typically larger and heavier, throwing off the balance of the rifle. I have seen high magnification scopes as the cause of more deer getting away than a simple 4X. You can use a 4X scope effectively at over 300 yds, but you are gonna kick yourself if you need a quick shot in the brush at 40 yds and you have a 10X.
I too have had friends and family think their scopes are shot, they come to me(has happened with everything from Tascos to Leupold VX-IIIs, I fire a few rounds, if there is still a problem, I clean the gun. Fire a few more, if problem still exists, I mount the scope on one of my rifles that I know the accuracy of, if the problem goes away we know it isn't the scope. I continue the process of elimination until the culprit is found. About 25% of the time, they just can't shoot, 25% of the time, it is a badly fouled barrel/damaged crown, ~30% of the time rings/bases are loose, ~10% of the time it is a junk scope and the other 10% is action screws being improperly torqued. I have never ran into magnification as a "glaring issue", even with 4x scopes it isn't a problem to get close to or exceed 1" at 100yds. Once they start grouping in the 2-3" range it is time to start looking at ammunition, and after 2-3 boxes of different stuff we usually get it down under 1.5".