My folks only have WiFi on vacation, what is the easiest messaging app to bridge from iOS to GrapheneOS wo/GP?

https://lemmy.world/post/4159462

My folks only have WiFi on vacation, what is the easiest messaging app to bridge from iOS to GrapheneOS wo/GP? - Lemmy.world

Need something achievable for an extremely tech illiterate person on iOS. I got told about this after they are already gone and have no access to the device, but am asked to solve the problem.

As others have pointed out here, Signal is a very good choice.
If they do not have cell service, they won’t be able to set up Signal, or any other service that requires a phone number (they won’t be able to receive the text message that verifies they own the number).