FaceTime audio won’t come through AirPods on MacBook Pro

When my friend calls me over their MacBook Pro through to my iPhone, while they have AirPods connected, I can only hear audio that comes in through their MacBook’s built-in microphone. They can hear me through their AirPods, and my own AirPods/iPhone work just fine. I just am not getting audio from their AirPods, instead the audio from them being sent to my AirPods is from their internal MacBook microphone. They have tried changing audio outputs/inputs both in the FaceTime application and through their laptop settings. It hasn’t worked. Has anyone had a similar issue, and how did you fix it?