I'm here with my mum at the moment. I can't actually stop her driving. If I report her, she'll know it was me as I'm the only "sane" passenger she ever has, and that will be then end of our relationship. Her doctor won't talk to me as I don't have power of attorney and mum won't agree to me having it. As far as she's concerned, no accidents means she's safe.
She's also my dad's primary carer, and they live rurally. No licence will have a massive impact on my dad's level of care. Public transport is very unreliable in their area. There's little chance of children in the road near there, more likely she'll miss a pothole and catch it hard.
I'm hoping her attitude changes when he passes.