CTP (compulsory 3rd party) is with the vehicle, it's a requirement for its registration. I think it would be safe to say that the car manufacturer and/or dealership that gives him the vehicle would have registered it hence a CTP would be in place in their name.
Note the "3rd party" terminology, that means not the driver of car #1 or the driver of car #2, the 3rd party/parties would be the passengers in the Uber. Hence their medical bills, loss of work etc would be covered by Mams vehicle's CTP.
The important question in this case would refer to the comprehensive insurance that it would be reasonable to assume was taken out by the car manufacturer and/or dealership that gave Mam the vehicle. Most comprehensive insurance policies require that the driver of the vehicle be licensed and, in some policies, that the driver be not intoxicated or drug driving. Since Mam was both of those that could mean the comprehensive policy would be invalidated. In those sorts of case it is quite common for the driver to be personally responsible for repairing/replacing both vehicles by the insurance company.
I would say the chances of the Donkeys paying are pretty much guaranteed, for the repairs to both and/or the written off cost if they aren't repairable. Once again Mam escapes what a "normal person" would be paying for.
Team First