How do I deal with meddling siblings (of my parents) and navigate my own grief?

My mother and father both came from large families. My mom was the oldest of 8 and died just two weeks ago. Talk about a blow. She was diagnosed with her third round of cancer (beat two) only 5.5 weeks before hand. I traveled back to be with her (I live across country) and immediately her brothers and sisters started in on me. She was clearly dying and they were telling me how wonderful their relationship was with her and how she lit up when they visited. She was rude and horrible to me, telling me I was wasting money and to go home. I know that was the disease and meds talking but dang it hurt.

After she had a stroke and her kidneys failed, we were told hospice would be the best for her. My father and I made that decision after seeing her having to be restrained to stop from hurting herself. She was in horrible pain, out of her head, and screaming for me to stop people from hurting her. I remained strong for my dad but I will never forget that.

My mother's brother (we'll call him Steve) and sister (we'll say Tammy) wanted to be a part of the decision making. However, I refused and said the decision was my father's and that I was simply going to ensure he was okay making such decisions. When we returned to her room and I spoke to the brothers and sisters, Steve and Tammy told me I was being selfish and cruel to move her from the hospital to a hospice facility. They said I didn't love her and that I was going to cause her pain. I realize they were hurting but it really stung given that Steve said something similar to my mom when their mother passed away back in the 1980s.

At the funeral Steve refused to speak to me and shot me dirty looks at the pictures I chose for the video. He told my father that the obituary was poorly written and that I had been rude to him.

I spoke to my father about maybe moving across country to live with me. I could use his looking after me and of course vice versa. Steve, Tammy, and the rest have told me I am horrible for suggesting that. They said they will take him on and that I should quit my job to care for him full time. I'm not married. I have no children. I can't just quit my job and become a nurse. My aunt told me to get a job as a cashier and that would be better for my dad.

My father wants to try to live alone. He will for the next three months and then he's coming to visit me for 2-3 months. I told him we will see where we both are then and see if we can make it work. However, I again feel like this is between him and me, not his in-laws who are really making me angry.

I don't know how to cope with this. My father is going to be depending on these people for rides to the doctors he sees and small things. I will be managing his life the best I can from a distance. However, they want him to sign over power of attorney to them instead of me. They said they want to care for him and "will let me know" if I need to know anything. I have barely had time to react to my mother's death because I am on the defensive about these people.

Tammy basically told me the day of the funeral that my mother was like a mother to them and I would not ever understand their grief. I didn't realize it was a contest. I didn't realize I had seven new siblings when I was an only child. Tammy ran around the funeral checking on each of them and hugging them. She came up to me and asked if my dad was okay and if he was joining them for lunch. They are texting me to ask about dad but none have yet to ask about me or offer me any condolences. I don't know what to do at this point.

Do I insist Dad moves?
Do I let them take over his life and push me out?
Do I ignore them and continue to care for him long distance?
How do I figure out how to grieve and not go off on these awful people?