Lower Westrabidbee Dai put in £90m+ into the club, but it was given in the form of a loan rather than just pumping in money.
For simplicitity let's just say that Dai "borrowed" the money. The debt remains owed. Hence why the sale process was both protracted and complex. Both the ground and training complex are valuable tangible assets.
For additional simplicity / to avoid potential for confusion, if Dai borrowed the money, he still owes it to whomever he borrowed it from.
Neither Couhig nor RFC owe that money to the lender - if there is one.