Born too late.

Hi, all. I was born to a 47 year old father, who is now 66 going on 67. Most of my time spent growing up was court proceedings and custody disputes between a mother with drug issues; foster care thereafter, and survival mode after once more.
We got ''''lucky'''' around 7-8 years back, and were left a $500,000 trust for our father, w/ 2 sets of $50,000 trusts for myself and my brother, for college.
That 500,000 has dwindled to 80-90, after the purchase of a house, a new car, and a move to somewhere cross-country; as well as our father getting back into contact with his kids from a prior message and helping them out financially a lot, in the 30-60 grand amount. Seperate issue.
Now that I'm of college age, if a bit past it, I couldn't fathom not spending most of my days at home. My father isn't yet at a point where he's deteriorating mentally, but he needs help with a lot of stuff. Occasionally getting up, not able to make food all of the time, needs someone to drive, a bunch of little things that combine with health issues where he had a bout of about 6 months of being in and out of comas for a calcium imbalance that would've been fatal without us here to see the day by day change, as he was able to act entirely normal to our half-sister on the phone.
My brother & his partner moved to New York in November-ish of last year, and stayed until March, when a brain tumour was found in my father's head. They flew back for this; as well as because their roommates weren't good people. Now, barely 6 months on, they want to move into their own house. I understand this desire for independence, because I want it too, but I don't see a world where nobody can live in with our father, and the fairest thing to me feels like splitting the load and perhaps just pooling savings for a larger property we feel more happy in. I have a laundry list of my own issues w/ PTSD, Depression, AuDHD, and there are times like now where I've not left bed for a month+, and struggle some days to eat even 600 calories. I'm barely in a place to take care of myself, let alone someone else, especially as aging continues. In contrast to this, my brother and his partner are very self motivated, out almost every day, and energetic.
I'm looking for advice on that topic, and perhaps how to talk to them and sort of talk it out, as well as if it's even reasonable to have such an opinion on their desire to move out again.
Additionally, I didn't get to make many memories with my dad. There's so much cool stuff we want to do but of his more serious issues, walking a moderate period is one of them, and a lot of our interests are museum based. Obviously 66 isn't a terribly old age by modern standards, and he's adamant he'll make it to 85, so there's 19 years, but things are going to get more hard, not easier, and I feel so lost and scared with how things are, and so guilty for being so tired and lacking any executive function to want to even do these things, or do anything but sleep and lay in bed.
I don't want to scare my brother, so, I'm asking all of this here.
For a less personal part, my father is 10% disabled per. the VA, but is on medicaid. With the prospect of fulltime care, I need to look at how to buy groceries, so if anyone can help with that process through either of those, or even a third party if it's easier / preferable, I'll take whatever information I can consume.