>>>It's already a very small house and as far as I am aware, only worth around 180000
A small house (such as the one I live in) around here [in a very pleasant part of the lovely county of Suffolk] costs around £100,000. Perhaps your friend has links to a cheaper part of the country than where she now is, so that she could move home, while still being close to friends or family, thus solving her financial problems?
Otherwise talking to the lender might be worth a try. A friend of mine managed to extend her mortgage (thus lowering her monthly payments) twice after she'd reached retirement age, so it's certainly a possibility.