If this car that is being bought is going to be for his mum in the long run surely the best thing to do would be to ask her what she wants from a car, besides it being an automatic, then come back to us with her preferences so we can make an informed choice for you. Get a car which your mum likes and grin and bare it until you get your own car, I wouldn't get her to make sacrifices. There are thousands of cars which can be had with an auto box. Does she want a hatch back, convertable or a saloon? Does she want a petrol or diesel engine? Does she want style, reliability or a mix? There are loads of questions to be asked.
That's just my opinion, don't take it the wrong way but it seems like a suitable idea.
To be fair, a brand new car can turn out to be even more unreliable than a used car. If you choose the right make, with a car which has a shed load of service history with all of the usual needs done the chances are it's going to be as good as one off the forcourt and you will get a better car for a better price.