The board can vote to waive it. That's... how boards work. They could vote to waive Junior's and Nunes' lockups, too, if they wanted to. The only recourse shareholders would have is a lawsuit.
Edit: And if you don't want to believe me, maybe you'll believe a professional financial writer:
https://www.bloomberg.com/opinion/articles/2024-03-19/banks-can-get-emissions-off-the-books
Also, Trump’s shares are subject to a lockup agreement, so he’s not allowed to “lend, offer, pledge, hypothecate, encumber, donate, assign, sell, contract to sell … or otherwise transfer or dispose of” his shares for six months, which presumably covers using them as collateral for a loan (or appeals bond). But the agreement is between Trump and DWAC, and DWAC could just waive it. It is not best practices or anything, as a capital markets matter, to waive the lockup an hour after the merger, but I think it is possible. Ordinarily you don’t do it because shareholders will be mad about additional shares flooding the market, but (1) if he just pledges his shares to a bank, they won’t flood the market, and (2) the shareholders are presumably Trump fans and will be happy to help him fund his legal bills. Probably the stock would go up if they gave him a limited waiver for this.
Edit 2: This, by the way, is why folks are so critical of the Tesla board and why Elon's recent pay package was rescinded by a judge, who determined the board did not act in the best interests of the shareholders by approving that package; rather, they concluded the board was too close to, and too beholden to, Elon to be able to effectively negotiate that package.
Boards are basically the last line of defense when it comes to things like pay packages and so forth, but that doesn't stop shenanigans from happening, hence shareholder lawsuits, which are basically the final recourse for shareholders to hold boards to account.