Right, that's the only way out of the box. If Moshiri takes less, and the remaining money (from a more qualified buyer) goes to paying off debt, nice things happen. One is that the more creditworthy borrower, with access to the UK banking system, can finance the rest of the stadium at a more attractive rate. The loan would also be better collateralized, which would help with the interest rate problem. The other would be that we would simply have less debt.
The long and the short of it is that any sale which does not result in Moshiri fully realizing his losses resulting from the fiscal mismanagement of the club will destroy the club. He is the only one that wins, if he receives an above-market price for his shares. The buyer and the club both lose.