I'm a bit skeptical with this kind of stories, because there are people who make up stories on the forums and we have no way to check if they are telling the truth or not. I'm not saying the story is true or not, I'm just saying I have no way of knowing.
Just go on with the story
. Be happy for the person who forgot his BTC holdings and just remembered recently selling it at $20k. That amount of money is indeed a life changer in my country. But sadly he couldn't wait anymore and could possibly get 5x of the sold value if he waits 2 to 3 years from now.
To me, what stories like this remind me of are the contrary stories, the stories of people who have been around all this time since Bitcoin was created, who bought high and sold low. Many of them are now Bitcoin haters, who after losing money decided they wanted nothing to do with Bitcoin, and are waiting for it to go to 0, as a way of confirming that they are right for not buying again.
There is always another side of the story like my friend who happens to have 12 BTC way back in 2016. He sold it for $2000 dollars in the 2nd quarter of 2017 and months later BTC surged. Later he told me that he regretted selling all his BTC that early.