The judges are seemingly creating loopholes for Sharifs to fall through, otherwise even a village idiot knows that financial matters cannot be proven through letters, regardless of where the letter came from. Just because A writes a letter saying he gave x dollars to B, doesnt mean he gave it. He has to show a copy of the check, bank transaction record, or some evidence. And if the person is claiming that the transaction was in cash, even then, at the very least, there would be a receipt.
Supreme court is intentionally giving wriggling room to PMLN...thanks to the threatening press conferences from PMLN leaders...otherwise letters like these are usually tossed in the bin the moment they are presented.