Need to vent!!!!

So I'm a nanny. Have been for 20 years. I've worked for my brother and his partner for the past 4 years. Never have I recieved a bonus, never have I recieved a raise, I dont even get paid for gas when I take her places. I teach her school every day, I do all her laundry every week, I clean out her closet in spring and fall, I clean out her toy room when needed (removing toys for donations)I take her to her Dr appointments, I take her to dentist appointments, I even take their dogs to the vet I do everything for them! Today my niece and I were playing outside in the water table and her neighbor friends (who were playing at my brothers house Monday night after i had left for the day)came outside and were talking to us. The eldest child informed me that her mom just tested positive for covid! Her little sister was standing next to her, she started school last week so she should have been in school. Then the eldest one further explains to me that the school put her little sister in a room all by herself with one book until her dad went and picked her up. Then she tells me that she wished my niece could go to her birthday party this Saturday but because her mum now has covid the party is canceled. So by now its 9am and I told my niece time to get dressed because it was time to do school work. So my niece goes upstairs and I go to my brothers in home office and tell him what the girls just told me. He doesn't believe it of course and tells me the girls are probably lying to me. He's a trump supporter so he doesn't care to think too much about covid. So I leave him and go sit at the kitchen island and text my fiance who has a compromised immune system because he had diabetes that the girls were here Monday night and I've been exposed. So now im really concerned about my family at home. Then my brother comes into the kitchen and starts with they're just telling stories and I try to tell him they're not lying. Her party is canceled and her little sister who should be in school is home! Again he blows it all off saying well then why didn't the mom tell me? Saying he just saw her the other night and she was fine. 🤷‍♀️ I dont know Michael why do you go ask them im not her i can't answer that! So he asks me if I'm scared I said yes I have a family. And my mother inlaw has cancer so yes im very concerned. If I've been exposed then my whole family needs to be quarantined my eldest daughter works at target like yes im concerned! He told me then if you're upset then go home! So I'm like im not dealing with your stupidity so I get up and go to go upstairs with my niece to see if she's finished getting dressed and he screams at me to get downstairs and get away from HIS daughter! After that im like fuck you I grabbed my shit and left! My brother isn't even the one who pays me for my services his partner does! My brother can go and fuck himself. Screaming at me and kicking me out because I'm concerned about the safety of my family has more than crossed the line. He has always been a selfish douchebag and he still is! Sorry for the long post I just had to let that all out.