Save our home

2 years ago, my grandad passed away from a battle with dementia. Myself and my mum had to care for him for awhile until we had to put him in to a home for rest-bite because my mum was struggling to cope and I was doing exams. During this time my mum got the unfortunate diagnosis of breast cancer so my grandad had to remain in a care home, when we put him in to this home we were told it would not cost anything. A few months in we started receiving  letters stating a cost for his stay not long after this he passed away, after this we got a letter saying the cost for the time he was in there was £6000, we were told we would be able to pay this back gradually every month. Which we have been doing. Fast forwarding to today, they have demanded that we pay the remaining amount of £5000 which is impossible for us to do as we struggle enough as it is and so they are threatening to force us into selling our home to pay the remaining amount, this is not something we want to do as it is one of the remaining memories of my nan and grandad that we have as a family and we can’t afford to move elsewhere. Also our house is equipped with everything my mum has to help her with her health. My mum also has heart failure and I’m worried about the stress this is causing her as it’s making her more ill. Any help would be much appreciated. We don’t have a lot of time to raise the money.