She is becoming increasingly paranoid and hostile. She runs into small issues (today her web browser window was smaller than normal) and gets very angry, blames members of the family, curses at us, yells, and calls us names. She generally seems mean and spiteful, and many of her comments are very hurtful. Her memory is showing signs of fading, she is slowly working on a hoarding addiction, and has less and less time for her family. Her addictions (online shopping, hoarding, wine, candy crush) are taking up legitimately more than half of her day and getting in the way of her relationships. She is convinced that her children are constantly out to get her and expects complete subordination while she calls us "pieces of sh*t" and yells because of something trivial. Lastly, she has begun seriously overfeeding our cat, 3 or more times a day. When we bring this up, or anything for that matter, she gets angry, tells us were spiraling out of control and projecting, calls us d*cks or something, and goes on doing what she was doing. My father works a lot and just can't- or wont- see this. Recently i have been thinking she needs help, and its only gonna get worse, but im not sure what steps are appropriate to take. She refuses to hear it from us, but she needs help.
Go for guardianship
Walk away and let whatever happens happen
With guardianship you can take over her finances and cut off her spending. I don't know if she's paying the bills in full on time or if she's behind, you didn't say. Late or unpaid bills is a sure sign someone is mishandling their money. I don't really like the idea of handling someone else's money, simply because one of two things usually happens. Either the person for whom you're handling money starts falsely accusing you of stealing or the person handling the other person's money is actually stealing. POA or any other position where you handle someone else's money is actually a license to steal according to what I saw online posted by an actual lawyer when I was doing my research about elder financial abuse. Usually the person doing the stealing is usually someone closest to the elder like children or grandchildren, siblings, even friends. According to what I saw in a YouTube video from a lawyer, POA for instants is a legal license to steal, especially if you give the POA full powers since they can do anything and everything just like a guardian can. Knowing what I know now is why I mentioned the other option of just walking away and saving yourself the trouble.
Walking away and let the cards fall where they will
Walking away will save you the trouble, even for worst thing you're going through now but there's coming a day someone else will end up taking guardianship of your mom and it may not be someone trustworthy. I don't know if you ever heard of abusive guardianship, but it's a very real problem. The bigger problem is no one seems to be doing anything to stop it. There are three parts to a video on YouTube titled, "how your elderly parents will become wards of the state". You may want to watch each one of these in order and pay close attention especially to part one because it gives the biggest of the problems on how the award is kidnapped even when they don't need a guardian because usually only the wealthiest our targets. That's because all you need is some age and wealth because they can use your age against you to target your wealth and kidnap you, institutionalize you and forcefully drug you once they get you there. When you're drugged and out of it these special courts give the guardian the go ahead to do whatever they want including but not limited to liquidating all of your wealth, changing and overturning any legal protections you had in place to protect yourself, and when you die they have you cremated whether you wanted it or not and they almost never tell the family until much later. If you run out of wealth before dying, the ward usually dies only about two hours after the last time is spent or they are released from guardianship with nothing, just turned loose into the street with absolutely nothing. If you don't believe me and what will happen if your mom becomes a ward of the state, go look up that video for yourself but pay special attention to part one of "how your elderly parents will become wards of the state". You may not believe me but you'll believe someone else who actually did their homework and uploaded that video and you'll also believe others who have been there and seen their loved ones become wards of the state like I have with my foster dad
Stress is another challenge to consider. Stress could be brought on by health problems, but relationship issues can also bring it about.
You stated that your father works alot, and it sounds like he's out of touch with what is going on? Is he not experiencing the same problems with your mom as the rest of your family? Him being gone much of the time may also be contributing to her behavior. Or, if he was abusive to her then he may be the challenge for her. You didn't mention much about him other than his work, so I'm just brainstorming with that as a possibility with little to go on.