Mugged My Parents

Hello and I hope you can help us.

My Father passed away last Sunday and this week

He borrowed Ł40,500 on the 9th April 1998 from the Bank of Scotland under the SAM 06 scheme.

The base price of the bungalow was Ł165,000 and it has been recently valued at approx Ł330,000.

The Share of appreciation was 73.63% so to pay the loan back will cost approx Ł162,000. This does not leave enough for my mother to be able to move.

I am amazed that a bank is allowed to basically mug old age pensioners. These loans must have been miss-represented or miss-sold.
Why was there not a cap on the amount to be repaid?
How can I help?