Does your family's threat model actually include targeted surveillance by US intelligence agencies? There are many reasons to switch off whatsapp, but I don't believe it should be considered insecure unless you are a journalist, activist, or citizen of a country with severe oppressive regimes: China, Iran, Saudi Arabia, Turkey, Russia, etc.
If your threat model DOES include US intelligence agencies, you shouldn't use almost any mainstream browser, most protocols (including https://), social media (including HN), etc...
If your threat model DOES include US intelligence agencies, you shouldn't use almost any mainstream browser, most protocols (including https://), social media (including HN), etc...