Helping my dad find a diabetes device he can actually use

My father has diabetes and his eyesight isn't as good as it used to be. We are looking at different glucose monitoring options, but I'm not sure which features actually make a difference for older adults.

Things like larger numbers, voice features, easier buttons, phone apps, alarms and sharing results with family all seem useful, but I don't know which ones matter most in daily life.

For people who use these devices themselves or help an older family member manage diabetes, what features have made the biggest difference?

I'm trying to find something that is simple and practical, not just something with lots of features that nobody ends up using.