My friends use Element since it has become a lot less buggy in my experience in the last few months, and is feature rich. Given the apparent requirements (calls, location sharing, etc), I don’t know if there are any other android clients that offer everything you’re looking for. If it’s been a bit since you’ve used Element, I would try it again. Could even have unencrypted (group chat) rooms depending on security requirements since all accounts will be on your instance to avoid encryption issues.
Matrix
An open network for secure, decentralized communication
Try schildichat
Lots of people complain about Schildichat for various reasons, but Element for Android gets unbearably slow for me after less than a day of use. Clearing the cache resets the timer, but it just keeps happening. That doesn't happen on Schildichat, and those two apps are the only ones I know of that support both spaces and threads, which I need.
Wait for element x to come out, I had terrible experiences with trying this
I wish they organized the rooms list on android better.
I favorite person to person and rooms I admin and the random rooms I am in push the rooms I care about down all the time.
maybe a hot take.... but beeper. makes it way easier to manager the keys and crap with an email login for those that loose their passwords all the time. and linking their other favortire socials might be a selling point. but if youre super cautious/paranoid, they have ways to run your own server. (i use their servers...)
If they don’t care about the protocol, choose a protocol that doesn’t take minutes just to join rooms & has clients that use less data/power so the family isn’t annoyed to have that app on their phone.