Then like a year later he's buying them back. I swear he has games that he's bought at least 3 or 4 times over.
I used to do that, I'd hit a point where I wouldn't have time or inclination to game for awhile and I'd look at my collection and think "what a waste of space and what a waste of money this was" then dispose of it for little cash, every time thinking I'd 'outgrown' gaming. Typical kid, wanting to 'grow up'. Gaming is my hobby, it always will be.
3 or 4 years ago I started again having only been left with the PS2 games I couldn't bear to part with and literally a couple of PS1 titles. Gone were all the Megadrive games I'd owned before several times, my PS1 collection (all the Konami, Namco and most Squaresoft games I owned from new, Klonoa, Symphony of the Night soundtrack edition, the works).
Now, after a lot of bargain hunting and trade-ins, my collection's larger than ever by a mile (in numbers at least), but there's several gaps in it when it comes to my favourite games from the past - so many of them are too obscure or too damned expensive. I content myself with knowing that I own several new treasures that I didn't have back then or weren't even released.
I do have to tidy the collection out every now and then, doing so now, it just gets too big, but the junk gets traded in for more gems so it just adds fuel to the fire. I will never get rid of my collection again - not only are the older 8/16/32 bit generation games becoming harder if not impossible to find cheap, there are so many recent consoles with ultra-obscure games that I can only get hold of now because online-enabled chain stores still carry that format. Rare/obscure PSP/DS/PS2/Wii games in the wild? No chance! Even some of the Wii U's ports and exclusives are starting to hot up already.
It is sad if someone is forced to sell their collection for whatever reason, or gives up on collecting only to regret it later, but sometimes people do just want to move on. It's best not to get too emotionally involved with what other people do with their things, as much as possible, life's complicated enough.