I would say a Corolla. Toyota make the most reliable cars I have ever driven. My current Camry has been run into the ground, I mean thrashed real hard, and she still runs. I've had her running weeks with but a drop of oil, had her running on 3 cylinders for a while, she's had a main seal leak for months and months (you should see the front of my house ). They have a good reputation for being a workhorse and rightly so. Also, if you start shopping around you will notice thjey keep their value a lot more than most of your small to medium capacity tin cans that come from Asia.
So my vote goes to any Corolla or Camry model from the mid '90's.
Good luck to your buddy.