He’s isolating because he came in contact with someone who has the virus. He doesn’t have symptoms yet.

The article clearly says he was “notified by the health services” and that “rules are rules.”

I’m not sure about being infected twice. I say this because it has been reported that Covid is rather stable - and not mutating the way the flu does. So, if you get Covid, whatever antibodies you develop should be perfect for the next time you encounter it.