I am not saying I sympathise with his mother.. She is doing a lot of harm to a lot of people's lives and using tears to extort peoples' tolerance of the destructive illness..
But I am saying that there are ways you can learn to work with the person with the illness...
I don't drive either, I have a license, but I hate driving, and for the same reason.. I am a tidy person myself, I understand her concern... Its HOW she manages the concern that's the probelm.
But I think accomodating her half way may reduce her panic and make her easier to work with... That and keeping as much in writing as you can...
The biggest problem is your H hasn't grown up, partly a result of this disorder I'm sure...