If he has tested positive six days ago and his fever has subsided, he should still be in isolation for 14 days. However since he is doing well and 10 days since his fever following tests can be useful
LDH
D-dimer
IL6 level
And
HRCT CHEST for CORADS scoring...
He might need a little bit of supportive therapy with fibrinolytic and monoclonal antibodies to take care of post Covid lung fibrosis.
Another Covid test 14 days after his onset of fever or test positivity...whichever is earlier.
Next Steps
maintain isolation
get the tests done
it's apt time for a HRCT chest and post Covid care
Health Tips
pls maintain isolation and quarantine for 14 days. but don't neglect him...care for him.