So he didn’t wear a mask?
What would him wearing a mask have to do with anything. The primary function of wearing a mask is to reduce the range and volume of the respiratory droplets that enable transmission of SARS-CoV-2. Him wearing a mask would have had little impact on his risk for catching it. Other people wearing their masks would reduce the risk, much like having airbags in your car reduces your risk for serious injury in the event of an accident. But people driving in cars with airbags are seriously hurt or killed all the time, because reducing risk is not the same as eliminating it.