Best mobile phone for a partially blind, very hard of hearing mother (89)?

I don't think you can force anyone to wear hearing aids if they are dead set against it. I've seen phones advertised for the hard of hearing that show on a screen so they can read. Maybe they have a large font she can see.

debinHouston, oh my gosh I spend a few years driving my Mom from the moon and back looking for the magic hearing aid that would help her hear. She had 3 new hearing aids in the past 5 years, all worked great in the doctor's office, but by the next day didn't work.... all due to user error.

My Mom also refused to have the wax removed from her ears because she didn't like the hot water, it was uncomfortable, so what happened was the wax attached itself over the years into her ear, thus without surgery it could not be removed. And being in her 90's surgery wasn't an option.

Now as for the mobile phone, I agree with cwillie and Pam above, it won't work. People your Mom's age are use to the old fashioned landline phones with the corded receiver. When it rings, you pick it up and say hello. I have landline phones in just about every room in the house, no need to search for that cellphone... now where did I put that thing???

And don't buy the portable landline phones. I had my Dad try one out and he would forget to push the button to answer the phone, and would forget to push the button when the call ended, thus a busy signal if I tried to call.... and half the time the phone was dead because he forgot to recharge it in the cradle.

Yep, good old fashioned landlines are still the best. Plus if there is an emergency and your Mom is unable to talk, the 911 dispatch will see on his/her screen the address from where the call was made, and they would send out someone to check the house. With a cellphone, unless you pay extra for exact GPS, emergency doesn't know where you are.

At 86, the only phone mom understood was an old fashioned desk phone from the 1970's. Find one with an adjustable volume wheel in the handset.

There is probably no mobile phone that will work well for someone with a visual impairment, because with every one you have to push a button to answer and that cause problems for elders that can see! Clarity makes some excellent phones for people who are hard of hearing, check them out online.
As for the HAs, it seems as though you have tried most things already. I was told that in ear aids are best for those with severe hearing loss, but you don't need to go for the tiny ones. They are hard to get used to, so maybe you will just have to be insistent that she wears them. It's just like glasses or false teeth, the less you use them the harder it is to adapt.
Is it possible to try ear buds with the amplifier?