Have him tested, if tests are available in your area , and if he’s negative, invite him in.
“Have him tested, “
Not an option.
Getting a test with a negative result is only good at that point in time, and needs to be repeated at least twice more to confirm that he doesn’t have it and just not showing it yet. If he just got done traveling to you that adds to his risk, such as gas stations etc. Again reschedule the trip!
All that proves is the relative is negative today.
Relative’s status can flip to positive tommorow.