Your sibling probably should get tested, but I can’t tell you where and why, that is a local knowledge. Tests are simple, and results will be known in a few days.
If you live in the same place, ventilate your rooms a lot. The higher concentration of virus in the air = greater risk of infection, and worse outcomes of the infection. (Often the first infected person in the household has the best outcome because everyone else starts with a higher initial virus load.)
Otherwise, the usual advice: limit your contact with people, wear a face mask, don’t touch eyes/nose/mouth, wash your hands, perhaps disinfect the stuff you buy with bleach or 70% alcohol, etc.
Your sibling probably should get tested, but I can’t tell you where and why, that is a local knowledge. Tests are simple, and results will be known in a few days.
If you live in the same place, ventilate your rooms a lot. The higher concentration of virus in the air = greater risk of infection, and worse outcomes of the infection. (Often the first infected person in the household has the best outcome because everyone else starts with a higher initial virus load.)
Otherwise, the usual advice: limit your contact with people, wear a face mask, don’t touch eyes/nose/mouth, wash your hands, perhaps disinfect the stuff you buy with bleach or 70% alcohol, etc.