Maybe he simply lost access to this address ? This is something rather common, sadly. And thus he might have said the truth when he said he sold all his coins.
It's a huge possibility. These are from 8 years ago and wallet corruption was a big risk. It's too bad that someone who was invested so early ended up being a complete moron when it comes to bitcoins. I doubt he sold everything but idk if he'd have access to these coins anymore.