Get her to keep the phone in a pocket or on a chain around her neck and turn on vibrate with ringer.
Have one of those, and they do work well, except when you get to the edge of the Bluetooth range. If mom lives in a small house or apartment, there will likely be no issue, but if the house allows you to get to the edge of the Bluetooth range, funny things can happen.
In our case, the XLink would hijack the microphone and speaker during a call (you were taking on the cell phone, itself, and everything would go silent. Only dropping the call, getting back in BT range, and placing the call again would solve the issue.
Reported this strange behavior to both XLink and my phone vendor, and neither even responded, let alone fixed the problem.
There are some phones out there designed especially for seniors with bigger number buttons and I think they also have loud ringer options.
Search for the best option, but here is one:
https://www.lively.com/phones/jitterbug-flip2/
Yup, that's what I did, and it worked well for me most of the time.
I did have to recycle power on the XLink box once in a while, or it would stop working. A reboot usually fixed any issue, EXCEPT for the weird behavior at the edge of BT range.
I also connected my XLink to the existing house wiring, and it was powerful enough to ring all the analog phones I had in the garage, basement, etc.
Like I said before, worked well except for the edge of BT issue, but since my wife had that problem several times and I had a very important call cut off that it took days to get back, my XLink is now disconnected.
Still wondering if the jury does come back with at least once guilty verdict:
RINOs will push to drop Trump at the convention and push IKKI NIKKI (who recently said she would actually vote for Trump) instead.
Don't think we have seen the end of the fuckery they have up their collective asses.
That's the point. Answer on the cell phone and starting walking around the house, or outside during a call, and suddenly the microphone and speaker just cut out.