Once you are positive in report its 100% positive.
But if you are negative in report and having symptoms there is chance that you are positive but there is some kind of errors in doing report like improper sample collecting/handling or sample is collected but the area where the bud wipes is clean without virus. So stick on positive report.
YOUR FATHER IS POSITIVE.
Next Steps
do some blood reports & take medications. For that you can consult me.
Health Tips
isolate them from other family members.