I must admit, I hadn't read this thread beyond the first couple of posts about someone excited to be driving a new car. I opened it up again to see 11 pages of, at times, quite vitriolic comments (on both sides).
Whether the OP is still here or not, it might be handy to look at a few facts:
DLA would be granted to his mother irrespective of whether she drove, got someone else to drive her, or used taxis. Taxpayers are not 'losing out' because she has this car.
Motability is a charity, and not funded by taxpayers directly.
The telling comment in the
statement quoted previously is " that cars must be used for the benefit of the disabled person". Obviously this statement isn' t the definitive text on the scheme, but the omission in that quote is "solely", i.e., solely for the benefit of the disabled person.
The OP appears to fit all the other criteria, e.g., lives with the car's keeper, uses it to drive her around.
There's no evidence that the OP has lied to obtain the car e.g., by selling on or renting it to anyone else.
He may have been a bit stupid by calling it, "my car", but does that amount to any more than a bit of over-enthusiasm? Maybe as the sole driver of the car he's had a disproportionate say in the choosing of it, but as far as I can see it's all within the rules.
An old Socialist maxim was, "from each according to his means, to each according to his needs", and I heartily disapprove of those who abuse that generosity, but this case appears at worst to be a slight bending of the rules and by no means the worst instance that I'm sure a lot of people here can recite.
In short, get a grip.