I think he's full of shit and doesn't have the private keys. I think his end game and next legal battle will be to try to use the courts to force mining pools to recognize Wright as the owner of those millions of bitcoins and give him access to the coins through a fork or some other way ... that even theoretically possible?
No, miners can't do anything there-- I mean anyone can create a fork of Bitcoin at any time, but the only way someone follows that fork is that they choose to adopt it. And no one but Wright would choose to accept a fork that steals coins for him. (He already has a fork that doesn't steal coins and it has well under 1% of Bitcoin's hashpower, way less than 1% of Bitcoin's value, and less than 40 reachable nodes).
Also in Wright's lawsuit against varrious former and current Bitcoin developers Wright states in a sworn statement that miners have no control ... so this would probably completely undermine his ability to litigate against any miners.
Wright's known ongoing attacks are:
1. File SLAPP litigation against journalists and community members to induce self-censorship of voices that call out his fraud. This is a key plank to his media control-- if you look at todays mainstream reporting they almost all universally repeat wright's laughably false narrative.
2. File spurious litigation to try to get control of bitcoin domain names. There was an existing lawsuit against bitcoin.org, which is still effectively ongoing because they've demanded like a million dollars in fees, he's also threatened a new lawsuit against bitcoin.org and bitcoincore.org for stealing the Bitcoin name.
3. File spurious litigation against respected Bitcoin technical experts, particularly ones who have discredited his claims of being Satoshi. Wright hopes to harass the remaining developers out of participating (and discourage older ones from coming back), and failing that destroy their reputations by trying to force them to create and distribute backdoored code that he's demanding. Wright also alleges that the developers lack any standing to challenge his claim of owning these coins.
4. Target developers with patent and "database rights" litigation, which he's also started threatening.
He may be attempting to take over bitcoin development by driving the reasonable OGs out and then adding new people who are secretly on his payroll, potentially operating under pseudonyms.
He's also threatened a number of large exchanges that don't list BSV, but it's not clear how important these moves are or if they're just for PR sake. Coinbase is already subject to dozens of lawsuits and against a company of their size and wealth another bullshit lawsuit has about zero intimidation effect. By comparison, to a volunteer open source developer a spurious lawsuit can mean a ruinous imposition of expenses and time, and really make it a poor personal decision to contribute.
Yes, if you scroll up on that page I linked to it also has more background information.