Not everything is meant literally. When he says they ended up with $0 doesn't have to be $0, just hugely down and nearly worthless compared to before that was doing well.
In the same way $100M could just have been $99M or even $80M, and then $0 they started with could just as well have been $20K in savings he invested.
The reddit poster goes on to comment:
>15 minutes phone call to decide to file for bankruptcy and for them to take their money back (and then some) and shut down my company
What? In no world would that happen. Even a mostly failed company has quite a bit more value than $0.
No mention of the name of the company or even the vertical. 100% BS.