Without being rude, I am certain I am not using audio mode. I use facetime a lot and am not dumb.
No one has implied your dumb. We always try to rule out the obvious first. Which devices do you use? Most issues my wife and I have with Facetime are wifi related. But your issue sounds different. You both might try swiping the Facetime app out of multitasking. Then do a hard reset.
7 Reset
Hold the power/wake button and the volume down button at the same time until the Apple logo appears. Then release.
Older devices:
Hold the top or side power/sleep button and the home button at the same time until the Apple logo appears, then release.
If that doesn't work, try Reset All Settings:
Reset All Settings
Go to Settings >General >Reset >Reset All Settings. This resets to default everything in Settings, including notifications, alerts, brightness, and clock settings like wake up alarms.