"Diabetes, Alzheimer's, severe motor and hearing disabilities: the list of pathologies incompatible or compatible under certain conditions with driving has been updated since Monday" - it's worth checking the above link (and a good French lesson for the day!)
Is this the same as in the UK? I'm sure my step-father shouldn't be driving anymore (although that's probably his one last pleasure), but his signs of dementure are very worrying.
