What should I do ?

Ok so I told my manager I was gonna need a couple days because my mom is going out of town she needs me to stay home with my sister but he thinks I’m lying because another employee is taking the same days off but I told him it has nothing to with her he said he’ll look into and I really can’t leave my sister at home and the thing is most people at my job do no call no shows and still have jobs and I think he’s only arguing with me because I don’t talk much so I’m thinking should I just call out those days