I hate my job

I work (temporarily) and a customer build food establishment. My last day is coming up this week and I’m so done. My family member had an emergency, so of course I went to their rescue, but my boss said “I’m stressed and I need you”. I wish I had the courage to say no. I hate it so much. They said “they can hand this alone right? I need you here I’m down staff”. No not All people can handle stressful situations. My family member has autism and bpd so this situation is very stressful and since they live with me and (family comes first) I’m not gonna abandon them in a time of need. I’m almost out the door anyway so why do you care if I come in? Other people call out all the time but lord forbid I call out for a real emergency. It’s not the end of the world but this situation is gonna set my family member back mentally for weeks. This is a traumatizing situation for them but my job doesn’t give 2 shits. Again, my job uses me as if I can do anything which I can but bc I’m not perfect I get reprimanded. I’m not perfect, I haven’t worked for the company for that long. I hate my coworkers and the customers. I only got this job to help someone else that I don’t even work with. Should I just quit 4 days early? Idk I feel responsible to go in after I finish dealing with my family member but I really wanna say go fuck yourself.