I h@te my dad and stepmom

Im so pissed off right now. My dad left us when my mom was pregnant with me. He has a total of 6 kids, three female and three male. He now has Alzheimer’s and needs to be looked after. My stepmom keeps telling me and my sisters that we have to take care of him. Keep in mind he never looked after us, as soon as he left us, he never gave any money to my mom, he never called to check on us, etc… My mom (alcoholic) barely took care of us, and didn’t claim child support either… and the useless piece of 💩 (dad) never cared. So now I’m supposed to care for him??? And the fact that my stepmom only tells my sisters and me to care about him, what about the men??? This is all so fucked up! And to add to the issue, I am the only one looking after my disabled mother… this is ridiculous