A family safe word is a secret word or phrase only your family knows, so if someone calls asking for money in a hurry, they have to say it to prove it's really them. The FBI's advice is to create a secret word or phrase with your family to verify their identity, because scammers can now fake a relative's voice with AI. A voice can be copied. A word nobody wrote down can't.
So what I'd do is pick something that isn't anywhere online, not the dog's name, your street or a birthday. Two odd words together works, like "purple gutter" (that's a made-up example, so don't use it). Tell it to everybody in person, not by text. The rule is the caller says the word first and you never give a hint. If they don't know it, you hang up and call them back on the number you saved, which is what the FTC says to do anyway. My guide to setting up your family safe word has the full setup, a practice call and a card for the fridge.