Well, this is exactly the scenario that confirms that the rich Wil keep getting richer, according to the story above, I believe the boy is from a very wealthy home and the money he used to buy monero back then might be his pocket money for the week or even half of it, which doesn't affect him in any way, and for him leaving it till now means he had enough to spend all along.

But imagine this was bought by a poor or middle class guy, he would have sold it a long time ago to get he's money back especially when he runs out of cash and theres already a good profit on that investment.