Accidental FaceTime calls, how to stop them?

My father-in-law loves group texting (iPhone 14, iOS 17.3) and lately, by accident, keeps group FaceTiming a few family members.

Often this occurs late at night, so of course, we think this is urgent. Never is, always purely an accident. But a 1 am FaceTime can be jarring.

He says he has no idea how he's doing this and we've never done a group FaceTime, just text.

Is there some sort of setting in iMessage where you can initiate a group FaceTime from a group chat?

The only other thing I can think of is maybe once we did a group FaceTime years ago, and for some reason he has that app open and he's confused/taps it by mistake.

[Re-titled by Moderator]