does signal's censorship circumvention work for them? It is also possible to use Molly (signal fork) which supports TOR via orbot.
If they cannot sign up in the first place, you could use SimpleX chat with TOR also via orbot, but you should figure out a way to send them your link or QR code without the government knowing, or they might get in trouble.
Molly (signal fork): https://molly.im/
Use TOR in China: https://support.torproject.org/censorship/connecting-from-china/
does signal's censorship circumvention work for them? It is also possible to use Molly (signal fork) which supports TOR via orbot. If they cannot sign up in the first place, you could use SimpleX chat with TOR also via orbot, but you should figure out a way to send them your link or QR code without the government knowing, or they might get in trouble.
Molly (signal fork): https://molly.im/
Use TOR in China: https://support.torproject.org/censorship/connecting-from-china/