Where do I begin?

I am helping to care for a Aunt of mine who is currently living in her own home, alone. She has always been somewhat reclusive. She has rapidly started (sometime following Easter) to become repetitive, forgetful, confused, blaming others for stealing her items, sometimes is very mean and verbally abusive. I have witnessed her slaming her hands down on the table or shoving her walker about in anger. She is also quite weepy (but then again, she always has been)
I know she is in some state of dementia as of late. She also complains of aches and pains however she REFUSES to see any doctors (I had even arranged for one to come to her home...but NO!) I try to understand what it is like to be her, wanting to go out and about but your body fails you. It must be very frustrating. I try not to let the hurtful things she says get to me (not so good at that) I am really trying to ignore the pot stirrers within the family who just see MONEY...and who try to confuse her and/or make me out to be up to no good. Another family member, whom my Auntie thinks is just swell (and as of late has assumed or been asigned???) all the pleasant aspects of caretaking, well, I have tried to get together with her, talk to her, show her documents...be an ally...and I get nice enough responses, but she is no ally, as it is becoming crystal clear.

I have ensured that my Auntie has groceries when she will allow me into the home. Otherwise that other family member does it. I was washing her sheets, but that was delegated, again to the other family member. I am allowed however, to take out her trash, arange for work to be done around the home, gather her mail, pay her bills, pick up her Poise pads, or in other words, the dirty work. I have spent time making sure she has a calender, and a grocery list to aid her with remembering what she needs and the items she likes.
She always expresses gratitude for the things I have done and for the fact that she knows I would drop positively anything to help her in anyway. I am not interested in praise, nor am I mining for compliments; she's my family, I would do this no matter what. ( I am doing this despite the occassional nastiness) What I don't like is being the "whipping boy", so to speak when she's angry or confused, or forgetful or when I feel like the family is attempting to turning her against me.
The family could have been there for this woman for the last 15 years when I was living far away, but they were not. The sudden interest has been sparked when it came to light that Auntie has a bit of money. Well, I am in charge of her finances, and could go before a judge today with suponeas for my phone/text records, all bank statements and hold my head high. I have done all for her, per her requests, honestly and with integrity.
One particular family member is very nosy (and has no shame in rapidly firing off questions as if it were the grand inquisition) I don't even know how to handle her as I am not a good liar, nor am I willing to share private information.
The other family member, who has rejected sitting down with me, is actually the only one who stands to inherit anything, but she has no clue because, again, she refuses to sit down with me and look at the documents.
So in reality, this famly BS is all for naught. But it is not my right, nor place to disclose this information. I was entrusted to do a job with integrity and discretion. But all of these people are stressing me out.
Anyone have similar issues? And what should I do???? Any advice iw greatly appreciated.
I just want to ensure that my Auntie is fed, comfortable, feels loved and is taken care of. I can deal with her dementia, but these other people are making things much harder for me to deal with all of this.
Thank you!