I'm upset because a friend of mine used to drive drunk about 7 years ago.
Why are you upset about someone driving drunk so many years ago?
Because I just found out he started driving drunk again and I'm disappointed in him.
It's unfortunate that your friend didn't change his behavior and is now drunk driving again. It sounds like he needs some help. You shouldn't hold a grudge against him and should try to intervene on his behalf.
I'm too frustrated with his behavior to try to help him.
It's understandable to be so upset when someone upsets you but holding a grudge is not going to help either of you. See if you can get him into counseling for his alcohol problem. He could seriously hurt himself or someone else.