My father has recently passed away away. He was only wage earner as my mother cannot work due to disablities she has applied for council tax benefit, housing benefit, incapacity benefit, widow's allowance and income support.
Not sure of your Mothers actual disability, but she may qualify for Disability living allowance and that is not means tested, along with Incapacity benefit. So savings do not affect these at all, could be worth claiming DLA ? the worst they can do is say she's not entitled.