Also, outside the US WhatsApp is some kind of standard the way rich Americans think iMessage is. Companies will ask her to contact them on WhatsApp, so she'll have to have it regardless of your personal involvement.

That really depends on the country that the family member is moving to, and is not an absolute thing world-wide.

Do you think signal's voice quality is not as good as whatsapp? It might be because they have less servers than whatsapp

Here goes to hoping that EU massages Whatsapp third party compatibility actually works. It would be great if Signal decided to enter the program, so that I could start recommending it to friends and family as a full on replacement, while not losing the ability to communicate with those who use WhatsApp.

I understand Signal stance, but it would honestly be better to have a mainstream alternative to Whatsapp that actually cares about privacy, rather than a niche product nobody uses