He only put up about 1/3rd of the capital himself, the rest was financed with loans that were put against the company, not himself. So if twitter fails he loses about 13 billion, a bunch of people who stupidly trusted him lose the rest, and he gets the write off so he can duck 27ish billion of taxes spread across a few years
He may be a moron in many ways but he didn’t get to 200ish billion by not knowing how to fuck people over and keep his money right; he absolutely knows how to come out ahead on this. It’s almost certainly why he’s so cocky despite running the company into the ground. Either the company succeeds and he then has a media empire that generates him healthy profit or it fails and he still comes out ahead. Either way he wins.