Ask HN: What's the best mobile phone for visually impaired people?

My dads vision has degraded over the past 10 years to becoming legally blind and up until recently he's always used an old flip phone with the text size set to maximum. I think he was mostly using memory when using the basic features but he still would ask me to help him with the more complex tasks.

His old flip phone recently broke and he asked me to find him a new phone that's more modern. I honestly don't have a clue where to start when searching for accessibility for phones, so I hope HN can help with this.