My brother may have corona virus. since we all live in the same house. is it inevitable rest of us will get it too? he mostly stays in basement but often hangs out in living room, at a distance. he had sore throat, now, only has his usual dry cough

Inevitable?: May not be inevitable if practicing a good self isolation for 14 days. No mention if he has fever. In these days may not be easy to get tested for coronavirus. They save the test kits for the severely ill patients who are hospitalized. The rest have to practice social distancing and self quarantine. So, if you develop more symptoms especially shortness of breath contact to your doctor or go to ER

Separation: Keep your brother's linens, dishes etc separate. He should live in a separate room for now. He should remain in quarantine for at least 7 days from the onset of symptoms and have three days without fever. Watch for similar symptoms and shortness of breath. If there is an elderly member of the family or someone with an underlying medical condition, consider separate housing.

Not inevitable.: Wash hands (or use sanitizer) often for at least 20 seconds. Wash hands before touching eyes, nose or mouth. Use a cloth cover over mouth & nose when around others. Stay home as much as possible. Avoid sick people. Distance at least 6 feet from others. Clean/ disinfect frequently used surfaces. Keep him physically separated from the rest of the family.