I'm not in real estate, but I have bought and sold a couple of houses. When I bought those houses, the seller asked for a certain amount. My lenders determined whether or not the amount I was asking to borrow was reasonable with regard to the asset. They weren't going to give me $500K to buy a hovel on a quarter-acre (where I live anyway, lol). Thus, it really doesn't matter what the seller (or in Trump's case, he who is suggesting the value of his collateral) values the property at. Responsible banks will independently evaluate the value of the collateral and base their lending decisions on that valuation.
Unless I'm missing something here, I'm not really sure why this is so difficult. Hell, in this case in particular, all you have to do is look at the values of the properties adjacent to Mar-a-Lago...
This seems to me to be a bold and bald-faced political persecution. And if it is, that should concern every American citizen - right, left and middle.