Don't get anything volkswagen..... Considering all that's happened here in the states.
It's not only in the US and it's not only VW. VW, Škoda, Audi, Seat all of those are under VW group and all these companies have used the same illegal software. He can still get a VW as long as it's using petrol and not diesel.
I'll go with Audi because I like them the most, there are quite a lot of them here and I'll be getting one myself rather soon. Petrol/gas engine of course combined with LPG, no thank you on diesel.
Can't tell you which model of Audi to get as I don't know the price ranges of used cars in the USA, but I'll be getting a used 2010-2012 A4 for around 10-15k euro. That being said, I won't be buying it with monthly rates but with cash as I'm taking a loan from a bank.