Meanness

I used to think that families fighting over money was something that happened to others. Nowadays, I have to recognize that it's a disease that has recently touched mine.
Some years ago, my father's father lost his sight. At the beginning we thought he was not completely blind, because he could manage to do some things which required sight. Out of his blindness, he started to behave in a violent way. At that moment, his doctors recommended giving him some pills to calm him. My aunt refused categorically. Then, my father and my uncle suggested to bring him to a place where he could receive the special attention he needed, but my aunt refused again, and offered herself to look after him.
Things were good, until the house where my grandfather used to live was sold last year. The money they got for the sale, was divided into four equal parts, one for the father, one for each brother, and one for the sister. When they made such division, my father agreed with his siblings to leave my grandfather's part untouched, until they decide to admit him in a good resting place which might demand more money than the full amount of his pension.
This agreement was great. My grandfather was still living with my aunt, and nobody complained about it.
Out of greed, nonsense, or whatever reason I don't care much at this point, my aunt came one day this year, gathered her brothers, and informed them that she had spent all her money, plus my grandfather's money. My uncle wanted to kill her, because he was counting with that money for the moment his father passes away. My father was shocked, and started worrying about his father's future.
When I learnt about this woman's deed, I told my mother that from then on, was a matter of time the moment in which her father would become an impossible burden in her life.
Sadly, only four months have passed, and last weekend my father's sister called him to say that she is suffering high blood pressure and she cannot have her father with her anymore. What's worse, my aunt said that my grandfather should be put in an institution here in Tucumán (she lives in Santiago del Estero) because she is moving to Buenos Aires to live with her oldest son.
Are you kidding me? How can you be such an awful person? My God!
She spent every single cent of my grandfather's fund, and now she simply flees?
The worst part is that my father is the only one who succeeded in having a life, which is why, as always happens, the one who never bothered others, the self-sufficient one, is that who has to take care of everything when things go wrong.
At this point, I only hope that my father's health is not put into any type of risk, or else, I don't know what am I capable of doing.
I've been taught that whenever I choose to do something or not do anything, I have to be responsible enough as to carry on with the unseen consequences that all that may have. That is why I don't understand this woman's reaction. What's more, I cannot understand why she sends me messages saying that her house's doors are fully opened for me if she is being such a bitch with my father, and was worse with me last year in relation to other issues which are too long to mention at this moment.
I suffered a lot with my mother's family because of their meanness, that's why I don't care about them, in fact I don't consider them part of my family anymore. Apparently, to avoid being hurt again, I will have to do the same with my father's family. And I wonder why do they have to be like that? Why should I build a shell around my loved ones to protect ourselves? We are family for Christ's sake! Why are you being such a pain in the ass?