Is it normal aunt always asks us for money

My aunt has always hit my parents up for money and my grandfather too when he was alive. My grandfather lent her money once but then she asked again and he would keep on saying no. After my grandfather told her no then she asked my parents for money and they gave her money and she has always hit them up for money and this has been going on for as long as i can remember (im 30 now btw). After my grandfather passed away, my 3 aunts and my grandfather's gf screwed my father out of the will even though we were the ones letting my grandfather live with us and caring for him with zero contribution from any of them. When it got so bad he needed to be put in the nursing home they refused to contribute anything but when he died they came flocking around like vultures and found a way to screw my father out of the will completely. The mooching aunt even took his car and gave my grandfather's gf the handicap sticker (i believe that may actually be illegal). The thing was my father was so mad at that point that he didnt even want to fight it and he told the lawyer to tell each of them never to contact us again. Fast forward a few years later my cousins that are the daughters from the mooch aunt tried to get friendly again with me and my sister. The oldest daughter is a trouble maker and i believe she gets her rocks off by causing drama all the time, but thats a different story. So anyway my cousin caused drama with me and then with my sister. Needless to say, we stopped talking. Since then they have been trying to get in contact with us and we have ignored them. My aunt called my dad after that and guilted him saying her car is old and she needs money for a new car. My dad avoided discussing it by saying he has to go. This makes both me and my sister furious. My sister and i both work full time. My parents own their own business and they work very hard. They are middle class but they arent rich and we would like to see them have a comfortable retirement. Its come to the point that next time i see them calling my parents house phone i want to pick up and tell her "im sorry, daddy warbucks doesnt live here anymore" and hang up. My aunt has two daughters who live with her and are perfectly capable of supporting her. My aunt had a pretty good job and im sure she gets money from her pension. Her father is dead and she got money from his will and then some and my parents got nothing. Has anybody else had to deal with moochy pesky relatives like this? This is fricking insane. I dont believe my parents are obligated to give them anything.