Most people - about 3/4 of the VI market who answered an online survey - use iPhone. Obviously this is a self-selected group so probably excludes many older people, or those new to sight-loss.

Have you considered an Echo? He could work verbally with one of those, and they're much cheaper to experiment with.

In my opinion the iPhone is the most accessible
With its Zoom feature, voice, and more accessibility features.
I also recommend if you are in the United States you look into Bard mobile a free audio book platform for the blind and visually impaired and blind
Hope this helps

I just used the Samsung A21 with the Talkback feature turned on. Can be found under settings.

iPhone 13Pro, 48 y old for reference and a total 😊

The great thing about smartphones is that you can customize then to the users needs. Dark high contrast themes, increased font size. zoom feature, talkback/voiceover. Mid range had enough power to handle everyday tasks, don't buy the cheap ones. Samsung A52 or A72 good mid range phones, S21 series high end.

I use an iPhone 11 Pro. I like iPhone because I’ve had fewer problems with them than my windows phones and android phones and you don’t have to learn a new interface each time you upgrade. Upgrades can be put off for a very long time if you have the battery replaced. If you don’t buy the newest model, pricing is reasonable.

iPhone with sporadic use of Voiceover - I have some residual vision.

Any smartphone would work, except maybe those uber cheap Motorolla ones for like $80.

Xiaomi Mi MAX 3

As someone who's grown up with low vision all my life, I strongly suggest you get your dad an Android. The accessibility fearless are excellent and you will not overpay for a phone. You'll also have many more options when it comes to things like navigation and daily living tasks. I have assisted many others in simila situations. I just got my Pixel 6 and it's also extremely adopt at things like reading human printed notes. I also recommend you get in touch with local state organizations. Also you can get your dad an NFB Newsline account which will give him access to nearly every newspaper and over 100 magazines. You can access this service with any phone (even a landline) or you can use a smart device.

I use an iPhone but I only got it b/c of my aunt, as I couldn’t afford one on my own. I used a ZTE before that! Androids are great for widgets. Check out this YouTuber who has some great videos on phones / electronics.
https://youtube.com/c/theblindlife

I'd recommend a tablet or an Alexa device if you're going the audible route. If you get him signed up with the National Library Service, the iOS app is better than the android app, as is the screen reader tbh.