I don't know what to do with my dad?

my dad is dying & I Have just turned 20 so my dad has diabetes a heart condition has a pacemaker & now has end stage kidney failure since I was 17 my dad has been sick & I have lived at home with him I done everything for him before work make him brekkie go to work drive home on my break make his lunch & then after work come home make his dinner then go thru apts that had been sent out for hospital visits drz etc would take time off 2 take him 2 all apt when he went in2 hospital I slept there after he got his pace maker put in 3 weeks later I could see him getting really sick & he would cough out blood etc but wouldn't go drz so I rung his drz & booked an apt behind his back which was lucky as it turned out he had silent heart attacks rushed him to the hospital and then they said they didn't thnk he wuld mke it they were wrong but yeah one of my half sisters I'm guessing was jelous of my dad & mines relationship has since started meddling she lived in aus so she really pissed me off when she tried blaming me for my dad going to hospital she would then say I'm not cooking good enough meals the house should be cleaner etc ( the house generally spotless and I've lived with my dad since I was 11 so I had to teach myself how to cook)my dad told me we had to go to this hospital apt and what I would find out I could not tell anyone I found out my dad had kidney failure I asked if I could give him 1 of my kidneys but due to his heart there was noway they would do a transplant he said he was not going to go on dialysis and it tore me apart now however my so called sister has told lie after lie about me and he he has taken her side!!! I have moved out & each time I try 2 c him etc she starts & he listens he hardly talks to me now each time we get close she finds some way 2 ruin it this has been going on 4 a year now & I'm feeling like I want to give up it but it has torn me apart thinking we were so close and he would do this to me help what should I do