Hi Lalicon,
welcome to the Apple (user-to-user) Community.
Re: "Siri commands for blind person"
Commiserations that your mother has recently gone blind.
Am no expert in this area, yet your post certainly deserves a reply!
Re: "Siri seldom (one time) works when she tells her to answer a call or to tell her who’s calling (one time)
and has never worked when she tells Siri to end a call".
Apple support has a helpful article online:
(NB: Article is for iOS 17, else please choose an earlier iOS version at the top of article for accurate info.)
How to: Change Siri accessibility settings on iPhone - Apple Support
Eg: says:
End calls with Siri
You can have Siri end phone and FaceTime calls.
- Go to Settings
> Accessibility > Siri, tap Call Hangup, then turn on Call Hangup. - Note: Available in select languages and on iPhone 11, iPhone SE (2nd generation), and later. Requires download of speech models.
- To end a call, say something like: “Siri, hang up.” (Participants on the call will hear you.)
You can also route and automatically answer calls or have Siri announce and answer calls.
More info: Set up vision-related accessibility features on iPhone - Apple Support
___________________
Vision aids on iPhone:
Hear iPhone speak the screen, selected text, and typing feedback - Apple Support
Hear audio descriptions for video content on iPhone - Apple Support
Use a braille display
Type braille on the screen
or
Apple's Accessibility Support Website
Eg: has:
Braille User Guides
Download a Unified English Braille user guide file (.BRF) for your device: Mac, iPhone, Apple Watch, Apple TV, or HomePod.
(NB: You can also "Get Support" from the link at the bottom of their website:)
Accessibility Support - Official Apple Support
or
You may want to contact Apple's Accessibility Support Team:
How to contact Apple for accessibility support - Apple Support
All the best :-)