Unfortunately, those are also being surveilled by Meta, so the exodus from Facebook did not help. Consider Signal or a private XMPP server.
replyI convinced my family to try Signal, and after a month of not being able to connect despite knowing each other's numbers - silent errors - I had to apologize and join them on WhatsApp.
replyThey all use iMessage primarily, but that's a whole other can-of-worms conversation. (Screw Apple.)