Covid-19 concerns in multi-family buildings.

Hello everyone, I have 2 multi (4 unit) buildings on the same property that I'm having and issue with a tenant that lives in one building but is always going into the other building to visit his "friend" after his walk to a nearby gas stationabout 5 times a day and the other residents don't like it because of the Covid-19 concerns. There is a shelter in place now so I think he should stay in his own building. I am thinking of sending everyone a letter asking to not have visitors during the shelter in place. Has anyone else had issues? 

 Also I have common areas cleaned weekly now should that be sufficient as far as "my part goes" or should I have them cleaned more now? Thanks