Is demanding 250,000 pounds instead of a debt of 72,000, based on a previous agreement, considered a usurious transaction, and is it permissible to bear witness to this settlement?

If a brother lends his sister a sum of money, he is not permitted to stipulate a benefit for himself; because a loan becomes void if a benefit for someone other than the borrower is stipulated within it. Any condition that leads to a benefit for a party other than the borrower invalidates the loan. A loan is only permissible if the benefit accrues purely to the borrower. Therefore, it is not permissible for the lender to stipulate ownership of a percentage of the borrower's residential unit. The questioner should not bear witness to this settlement, as it is Islamically invalid. As for the issue of inflation or changes in currency value, it can be addressed in another way. The preponderant opinion is to consider the value of the currency if there is egregious deception or a currency collapse, which results in significant harm to the rightful owner.