Barclays Family springboard mortgage - too good to be true?

[HelloToYou]

Aibu to think this is too good to be true?

Family member essentially opens savings account (which gains interest) to tune of 10% of house value... it isn't touched and they get it back after 3 years. (Unless mortgage payments are defaulted on)

You the buyer get 100% mortgage.

Catch?

Interest rate might be uncompetitive?

Saver person might need their savings, but they can't have them?

What happens if either party dies or cannot pay the mortgage? Will the savings be used in lieu of missed mortgage payments?

It's just another way of gifted deposit.

Also what happens if house prices drop and there isn't increased equity after 3 years. The deposit might have to stay with the bank rather than being returned to the saver.

If either party dies then we all have insurance, the house would get paid off.

The way it sounds is the money is not tied to the house and the saver definitely gets the money back after 3 years (equity / house price regardless) as long as mortgage payments haven't been missed.