Grandmother having phone trouble?

My grandmother is developing dementia and is half blind so we got her an iphone so she has a big screen and can display the words and apps bigger. She keeps managing to delete or change our contscts from her phone. How do we lock her phone contacts into her ohone so she stops deleting all her numbers?

You could ask the phone company how to go about doing that

In our experience, the large display size of computer-based technology is easily outweighed by how easy an older person who doesn't get it, especially if she doesn't see well, can screw it up.

(Yes, we tried a computer for my MIL when she couldn't read books any more, but she managed to delete books left and right, turn the display into other languages, and other fun stuff.)

What we found worked better was a press-button landline phone with big buttons and the ability to program frequently called numbers--the contacts list. Then near it you have a print-out in a huge font so she knows what button to push for whoever she wants to call. If the buttons are big enough, she may even be able to dial other numbers because she can see to do that.

Dementia and blindness are both very difficult for her to deal with--and for the family, too. Dementia means she's unlikely to manage an iphone any better than she does now. She's likely to do better with familiar phone types.