He also does not need to fund all of it; just enough that a bank would be willing to consider the Twitter shares he is purchasing as collateral for the rest of the loan.
I don't see this deal happening. He can't afford it (without exposing himself to unnecessary risk). If it does go through in the ways described here, he's an idiot ... and I don't believe that, despite my personal opinions about him.
Of course it's a lot of money and a lot of risk, but like him or hate him one thing Musk has consistently showed is that he's willing to take huge risks.
This deal likely won't haooen, but due to the poison pill, not due to the risk.
But in any case, my point was merely exactly what I wrote: he does not need to raise anywhere near the full amount, because he can utilize the shares he buy as part of the collateral.