Two questions.
My family insist on using Whatsapp for the family chats. I have to keep a copy on a device just so I can communicate with them. I do so under protest, as I was always told it isn't secure. My brother has just said
"oh Whatsapp is encrypted, it's perfectly secure".
First, is it actually as encrypted and safe as my brother claims? That would solve everything.
Second, if it isn't, where can I get some proof that we should switch to Telegram or whatever? Proof which doesn't make me look like a raving loony?
By typing in the numbers, or selectively sharing them from the address book. This works fine on Signal, Telegram and Threema. Only Whatsapp makes it so that you have to share your entire address book with the app.
With some workarounds you can actually use whatsapp also without giving it access to your address book, which shows that it is clearly an intentional dark pattern by Facebook to make people share their entire address book with them to avoid the hassle.