I can understand wanting to start off with a breeder your first time, since the odds of getting healthier rats if you can find a reputable one is higher. That's exactly what I did.
I will offer from hard experience that four is generally too young for a pocket pet, especially one like a rat. Seven and up is a much better starting age, and even then it both depends on the child and the willingness of the parent to supervise closely.
They have sharp claws much like a cat that often cause painful scratches and if they were so inclined to bite, which is rare, they can do some serious permanent damage to a child's small hands. Not to mention the much greater likelihood of a child accidentally injuring and killing the rat in a split second.
Though, you may be talking about it being 'his' rat in name only with you providing close supervision and care, which would be just fine.
I'll also suggest that you get two same sex rats. Most reputable breeders will not let you adopt them singly because rats are so social they often become depressed, nippy, and neurotic if kept alone.
Unfortunately there are not that many reputable ratteries in the south east. I'm in Alabama and there isn't one I'd recommend in this state. There are maybe two in Georgia. Phoenix Gate Rattery in Atlanta Georgia is the best I've found. She's ethical, knowledgeable, and has generally healthy, gentle lines. I've only had to take my rats from her to the vet two or three times total between five rats and I've had three of them for 15 months.
Starlight Rattery, of which I know nothing about, is the only rattery I have seen for Tennessee at all and I don't think they're breeding. Their website hasn't been updated since 09. The rest seem like flash in the pan back yard breeder types.
The waiting list for a rattery is going to be at least six months, and often as long as a year.
If you want to keep looking around yourself, Blackwolf Rattery has a list of 'red flags' to help you determine if a rattery is quality or not: