Persuading elderly parent to buy a new car

Definitely go the accompanied route.

I really didn't want to drive an auto but had to change as new van is only automatic. I'm mid 50s but adhd, so some cognitive deficits.

I like VW as they have a pretty simple dash, no flashing digital cockpit nonsense.

I'm back driving a lot, so it's not a case of being inept, just need to understand what's comfortable. So I'd say it's similar for your mum.

I now love my auto, much easier with my dodgy hip.

is terrified of learning her way around an unfamiliar vehicle

She’s right. Her driving days are nearly done and an unfamiliar car will be the end.

I would put your energy into looking at other solutions (taxis, local volunteer transport services, moving home, home visiting services etc).

Maybe an older automatic, of the same make and model as the one she knows would help? Ultimately though it is worth having a plan for when she can no longer drive. I'm already drip feeding to my parent the need to find a reliable taxi service as they also live rurally. I think their generation sees taxis as extravagant but if you add up the cost of cars and insurance and serviciing and petrol etc is not that expensive as a substitute.

Would she have a couple of lessons with an automatic driving instructor to get herself used to automatic controls? Might make her feel safer with someone else there showing her what to do (who isn’t a family member, as that can be very stressful at any age!)

Could she a buy a newer model of the car she has but not a complicated one.

She could book a driving lesson in an automatic just to see how it feels.

Mine had to get a new car at 80 because hers was written off in an accident (non-fault, she was rear-ended in a traffic jam). She switched to automatic and was anxious about adapting to a new car, also had never driven an auto before so she found a local auto driving instructor and had a couple of lessons then got them to come out with her for an hour in the new car when she got it. She was fine after that.

New cars are complicated! It takes a while for most of us.
If she is otherwise safe to drive let her continue in the car she knows. With kindness, at 85 this may be the thing that stops her driving. Living rurally is difficult without use of a car but millions do it. You may need a backup plan.

At 85 I would listen to her concerns. Is she still driving at night? Does she avoid driving in busy traffic or into large urban centres? Does she complain about how everyone else drives too fast and too close these days?

The reason I ask is because all those things would indicate to me that she is finding it harder to drive as her brain naturally becomes less able to judge speed and distance and react quickly enough. Over 80 most people struggle with this and adding a new car into the mix would be risky. Most accidents with older people happen when they respond in the moment and either judge speed and distance incorrectly or get confused with the controls. I wouldn't add a new car into the mix.

People have been pressuring my elderly Father to get a new car but for the reasons above I have encouraged him to stick with the car he knows and limit his driving to roads he knows well. He didn't drive at night anymore. I'd like him to stop driving soon but we aren't quite there yet.

Could she rent one for a few days to try it out?