The screen cap of the father's Reddit post which summarizes what happened:

Link to the actual post:

https://old.reddit.com/r/LinusTechTips/comments/t1e1if/you_destroyed_my_life/?sort=top

And a good "out of the loop explanation":

3 years ago NCIX had public auction to get rid of the last of the inventory and other items. NCIX was a Canadian electronics retailer, and Linus's former employer where he worked as the purchasing agent, and was the face of there youtube channel. There youtube channel was pretty much a proto-LinusTechTips. One of the main items Linus went to the auction to purchase was the play button from that channel.

as it goes in to in the message you linked, and Linus's response he didn't win the bidding, but while still there found out the young man and his father did, and tried to talk them in to selling him the button for what they paid, after explaining why the button was so important to him. The Son agreed but after hearing why the Son wanted it Linus told him to keep it.

after the video went up, the Son caught some flack and bullying from certain members of the LTT fan base that a few days later Linus called out. but I appears the situation scared the Son away from continuing to be a content creator.

Copied from:

https://old.reddit.com/r/OutOfTheLoop/comments/t2eix0/whats_the_deal_with_linustechtips_and_mindchop/hylt85p/