I'd agree. 3GB is what I'd deem entry-level these days. Even three years ago, I was using a 2GB graphics card and it was taking a performance battering at times - in almost standard HD resolution - 1920x1200.
Also as @SharkyUK says - installed game sizes are going up significantly - some breaking the 100GB barrier now. My main two drives are 500GB SSDs and I do find that I have to chop & change installs on them, due to capacity issues. That said, I'd have a 500GB SSD over a 1TB SATA drive any day of the week.
^^^ - this.
On a serious note - keep him in check with it or else school work might suffer.
In 1992 I managed to convince my parents that I needed a PC for my A-level Computing course. "It will help me do more coursework at home/I can do more coding away from the noisy classroom/I can work on it at the weekend..." All bullshit of course - I was a military plane g33k back then and I just wanted Aces of The Pacific pretty desperately.
In November of that year, I managed to get a PC ordered with a pickup for collection a week later. Pretty much minutes later, I was ordering AoTP from a mail order place and it arrived before my PC did.
I did do college work on my PC. I did do some extra bits that perhaps I wouldn't have done in class. But all of that was overshadowed by what this new gadget brought to me. If the time I used the PC for college work exceeded 10%, I'd be surprised. I can honestly say that that gaming PC was a detriment to my A-level results.
A few of my friends still game on 2GB cards and haven't found it limits them as they don't need more than 60fps at 1080p in medium settings. Granted, a few games it'll struggle with but if you're not enabling all the graphics settings they work fine. Here is just one of a few videos online proving this:
If you're just using the PC for gaming then a small SSD for the O/S and one or two larger HDD's for data or gaming is fine. Most games load quickly on an HDD anyway.
Of course, if you can afford a large SSD or a better graphics card, buy all means buy one, but you'd be surprised what you can game on.