You don't even have to believe him - you'd just have to believe (or see viable risk/reward) that he has a shot at a successful legal attack.
Wright claims to own around $50 billion dollars worth of cryptocurrency which he cannot access.
Let's say he manages to convince you that he has 1% chance of success at obtaining these funds-- something you could believe even if you know he's a fraud, you just have to have a low opinion of the courts and misunderstand how Bitcoin works (which many people do, see this discussion!).
If offers you a 10% stake in his victory, what would you pay for that? Well under the 1% assumption you might be willing to pay $25 million dollars (half the expected value).
The buyers error is just in flawed reasoning about the odds of success, but people are notoriously bad at reasoning about fringe events and a lot of people don't understand Bitcoin.
For Wright, the fact that his effort cannot be successful is actually a very good property: It means that he can safely sell more than 100% of his fictional fortune: He doesn't have to worry that he'll win and then have to pay out >100%. Instead, he'll lose and tell his investors "Sorry, gave it our best shot but you always knew this was a risky deal!". In that case his income from the scheme is only limited by how many suckers he can bring in... 100 people paying 25m for a '10%' stake would yield a 2.5 billion dollar windfall.
And if you don't think there are at least 100 suckers out there with 25 million to blow you haven't been paying attention to all the defi/ico/nft noise the last couple years.
Right now we know of one major self-claimed billionaire that Wright is exploiting, but there may be many others-- particularly in Asia where language barriers make it much easier for Wright to isolate victims from discrediting information.
He could offer his services to various blockchain-focused startups in which he'll fit right in considering said startups' objective is often to get money off clueless VCs by throwing the "blockchain" buzzword around (there are very little legitimate use-cases for a blockchain that can't be served by a traditional database, and a truly decentralized blockchain can't easily be monetized to the level a VC would want).
What is sad is that anyone is even talking about this guy. From the beginning people pointed out he is lying and yet he is still somehow able to be talk about.
Most obvious con-man that is still able to stay in public spotlight.