It is most definitely his money. He is using his real source of wealth, Tesla stock, as collateral to secure the loans. $44 billion worth of Tesla stock. And when you sell off a huge amount, as would happen in the case of the collateral being seized, it would tank the rest of his wealth which is mostly in non-collateralized (as far as we know, in relation to Twitter) Tesla stock. Investors knowing that $44 billion of Tesla stock will be liquidated--even if slowly--by creditors would make prices tank.

Elon's rich. Like all rich people, he is inherently immoral and opportunistic, holding no allegiance to his species nor country of residence ("world citizens" are a blight yet most countries still let them buy citizenship--that's true class solidarity while they get us fighting over stupid shit like transgender Chess Grandmasters). I have a feel that you are correct in that he's been earning money from the Saudis and Murdochs and many others. But the main source of his wealth is still in the market. A source which he pumped up with market manipulation because the SEC is a captured entity run exclusively for the benefit of the parasites at the top.

But it feels like arguing around the edges a bit. Elon is just not good at this. He has failed upward his entire life which is why he had to buy his way into basically every successful enterprise he is credited for. Rich people, especially nepo babies like Elon, don't succeed because they are better. They succeed because the upper class ensures that their class succeeds, because the alternative is the working class becoming their peers. And they can't have that.