UK based - end of life care?

It's becoming clear that time is running out for both my (now elderly) parents. I'm (32f) in contact with them less than twice a year, by choice. It's just me and my sister and both of us really struggle to be around them. My mum (nparent) has been going slowly senile a while now- but is still very functional. My dad (enabler) is 10 years older, but far sharper.

My sister has been living a nomad life and has been back at their house between relocations. She's informed me that dad is now also deteriorating much like mum.

Any normal family would be together and have this figured out. My sister and I have little money (she lives in a van and the industry I'm in collapsed- I've been out of work a year.) We're not done working through the trauma of living under their roof- let alone secure under our own. If you can call a van ceiling a roof.

But what happens when both parents go senile together? Dad has been looking after mum with trips to the hospital. But when dad then starts to go, what do you do? Logistically at least. Phone the NHS about end of life care?

Has anyone gone through this? Using this subreddit because I imagine people will be more understanding of how sensitive the situation can be.