My dog is dying and I can't do anything to help her

Sorry if this isn't tagged properly. Idk how to really tag a post like this. I don't post things often.

I have known this dog for over a decade, and had the honor of custody for the last 5. She is the last companion I have left after having lost my social circle, my home, and my job all within a month of each other 2 years ago. She has kept me from suicide, knowing that I cannot just abandon her like that. She is the world to me, but my world is getting on in years. She was 7 when I met her all those years ago. Now, she is an old lady and her health has been declining these last few months: eating less (not even soft food), losing weight, lethargy, expected symptoms of age catching up but also having a bad hacking cough periodically. This last week she has been getting even worse experiencing fainting spells, barely pooping with it being slimy/watery with discoloration if she even does, and her belly has become distended. These symptoms could be a number of illnesses but all of them are fatal if left untreated.

I am jobless thanks to mental health issues, neuropathy, and unstable housing on top of that. Been trying for disability and Medicaid, which I should be eligible for, but dealing with the bureaucracy of a deep South, Republican state is a nightmare that I cannot navigate. I have no income except trading SNAP benefits, which I trade with my mom for cash to get dog food and necessities. The only people I have in my life are my mom and my brother now, sleeping on their couch in the ass end of nowhere, after having bounced from couch to couch across the state. My brother is, unfortunately, the typical "fuck you I got mine" Republican. So, even though he has plenty of money (he brags about how much he has in savings constantly), asking him is a non-starter. My mom, on the other hand, is barely making ends meet as is. She cannot afford a vet bill and refuses to even contemplate trying to figure out how to help get my dog seen by one.

I have no one to express my concerns to. Anytime I even try with my mom (obviously, I have no relationship with my brother outside of being forced to exist in close proximity) just to have someone to talk to so I can deal with these emotions, I get brushed aside. Either she tries to offer half-assed "advice" that she found on reddit after hearing one symptom then ignored everything else I have to say only to then get mad when I tell her that it doesn't help to just grasp at straws trying to force feed my dog random medications because some random Internet stranger said it was "okay", or she just says "old dogs get sick and die; it's just what happens".

I'm being forced to watch as the closest thing I have to a child suffer, condemned to die a painful death from whatever illness is plaguing her, while those around me treat it like it's just some bad weather that will blow over and can't even be bothered to show even the slightest hint of compassion for what I'm going through.

So, I guess here I am, screaming to the faceless void of the Internet. Sorry for being a dark cloud on this day but I have nothing else I can do and had to vent.