AITAH for not being extremely involved with bfs dads health?

So my bf and I have been together for probably 4 years. Just a year ago we bought a house. 3 bedroom, 3 bathroom home with our two dogs. 1 bedroom is ours obviously, 1 guest bedroom, 1 home office (I work remotely) He learned probably just a year ago his fathers health was declining and needed some extra care.

Fast forward to a few months ago. He asked me if it was okay if his father lived with us. I at first said No. I, myself never grew up with a father and having another man that I've honestly never really met or spoke to living in my own home was not something I had wanted. But eventually I felt like I was guilted into saying yes. I had to basically move out of my home office and put my desk and belongings into the garage (this was winter so it was absolutely freezing in there) His dad eventually moved in and it's been nothing short of a fucking nightmare. (It's very clear that his father suffers some sort of dementia or alzhemiers disease)

The nursing home his father was originally in had explained to my bf that he was doing great, was able to walk, was functioning well and had no issues and would be fine moving into our home and living normally. Let's just say that was all a fucking lie! Ever since he has started living in our home he does nothing but pee everywhere. In the bedroom, on the bed, on the floor, in the hallway, in the bathroom. He probably goes through 15 diapers in a day. And not to mention there will be times I will be in my living room and he will just walk out but ass naked. It is just so stressful and I absolutely refuse to clean up any pee or do any type pee-soaked laundry. I only offer to meal prep food for him throughout the day and I will administer it to him from time to time if my bf is not around or home. I also do alot of the grocery shopping and essentials shopping for whatever his dad needs.

• This is where the argument begins - One day, his father peed absolutely everywhere in our house when I had gotten home from needing to work in the office. At this point, I had such a long day and I was so over walking into my house always smelling like human piss. I just walked straight to my dogs to take them outside. When I notice one of my dogs has been throwing up and having severe diarrhea. His poop was so odd colored, it genuinely looked like chocolate. (We'll circle back to this) After letting my dogs out, I had grabbed my swiffer and just cleaned the pee off the floor. When I stepped into the bathroom, it was absolutely covered in piss and the smell was horrendous, mind you the floors are PLASTERED with DOGGY PEE PADS. I literally gagged and walked away to the kitchen, where I noticed one of the snack cabinets had been touched. Specifically chocolate was gone, and this was chocolate my sister had sent me from her trip to Europe and the whole chocolate bar was missing. After futher speculation, I concluded that this man literally fed my dog chocolate and when I had asked him he was very quick to agree that he did in fact feed my dog chocolate. So naturally, I hate this man.

For the few weeks I've known this man, despite the issues he may be dealing with. He comes off so unappreciative and selfish and its so mind boggling. He consistently goes through our fridge and eats all of our food and basically scavenges through the house putting his unwashed hands everywhere and on everything. Its so filthy and disgusting, he even left a used diaper on the kitchen counter. It was absolutely horrifying.

I find myself working in the office more and having any excuse to just not go home. I hate being in my own home. My bfs other siblings and their wives live in the area. And occasionally they will come over to drop off snacks and diapers. Recently his dad had a doctors appointment and my bf freaked out on me because I am "selfish" and have "no desire" to help his father. He was upset that his brothers wife was at the doctors appointment but I wasn't. Can I just point out, I'm not married and I'm not fucking engaged to this man. Not saying that there isn't signs of that progressing in the future but fuck! I also worked during this "doctors appointment". I just feel like I don't owe him or his father anything, but to say I don't help seems ridiculous. I also don't even know this man at all.

I feel like I'm just trying to set boundaries on where I can and can't help and because I am doing so, that makes me a "bad" "selfish" person.

I just don't know how to handle this situation and would love some input and advice. I am so annoyed and upset with the whole situation.