"A lasting power of attorney (LPA) is a legal document that lets you (the 'donor') choose trusted people ('attorneys') to make decisions on your behalf.
An LPA is mainly used if you don't have the mental capacity to make decisions yourself"
This is the official government tool for creating a Lasting Power of Attorney, I helped my grandparents to create one and found the service really easy to use, no need to use a solicitor who charge a fortune for this.
Was £110 to register, but they've dropped the price to £82 and I believe you can get it for half price or even free if you receive benefits.
Well worth having to protect your finances and appoint someone to look after your affairs if you can't.