COVID Scare #2 Help???

My dad just got over Covid about two weeks ago (he doesn't live with us) Now my brother is having chills/fever, a sore throat/tonsils, and a headache. I'm not sure if it's the flu or Covid. He said his coworkers have become sick at all the same time. I've moved out of the bathroom we share and I'm really scared because idk if it's just the flu. He got it pretty fast apparently. Do y'all think he'll be okay? I know its different for everyone and he's in his room quarantined and my mom and I have been wearing masks whenever we have to see him. Thank you.