Actually, Akers Mill Road to Powers Ferry Road is a very common way to avoid I-285 in that area. From the Home Depot HQ, he could follow Cumberland Pkwy to Cumberland Blvd., and then onto Akers Mill, then make the left on Powers Ferry and head towards their condo.
When I lived in this area, I often went that way to avoid I-285 during the rush hours. It can be confusing looking at the maps because many of the roads share similar names and they overlap in a couple of areas.
It's certainly not the most direct route, but many commuters take that route to and from the area. Keep in mind, the area around I-75/I-285 at Cumberland is one of the worst parts of the metro Atlanta area during the evening rush hours.
Is 4:00 rush hour there? I know it starts about 5:30 here and is REALLY bad. People who get off at 4:00 avoid most of it. Just curious, since I've never been there!