There is really no story or explanation how the friend did it: reddit.com/r/wallstreetbets/comments/9bghv0/i_gave_my_friend_500_first_week_of_august_and_he/
It's luck, if you have enough monkeys one of them will hit the jackpot randomly and post on the internet about it. The real question is why aren't you posting the posts from reddit that show people blowing up their accounts? There's plenty of them. Like that guy who lost $200k to Walmart earnings. The person who made a million off of MU has probably already lost it all after the last 5 months since he said that he was still all in on those calls right before the stock dropped massively. You don't see him posting anymore do you? This thread is pointless.