I don't live in north Georgia, so I don't know the exact plants and trees that grow in the area, but I can make some educated guesses.
Wild black cherry/Prunus serotina grows all over the eastern United States, and it's host for both tiger swallowtails and red-spotted purples. It grows rapidly. There are several big moths that use this tree, and birds love the fruits. In my opinion, it's the best all-round wildlife tree you can plant.
Spicebush and/or sassafras host spicebush swallowtails, which also occur in that area, and birds will fight over the fruits on the female sassafras trees, so I imagine they also love spicebush fruits. Sassafras (and undoubtedly spicebush) also host several of the beautiful, big moths.
Willows grow in wet spots, and if your family member's property has a sunny, damp spot, a willow would host viceroys, red-spotted purples, and quite a few moths.
Hops tree/wafer ash/Ptelea trifoliata is an understory type tree/bush that hosts both giant swallowtails and tiger swallowtails.
If your relative wants to plant a garden, rue is a good start hosting both black and giant swallowtails. Milkweed, either the local type or Asclepias curassavica would host monarchs in the garden.
For nectar, he or she could plant butterfly bush in or out of the garden, coneflowers, Mexican sunflowers/Tithonia, lantana (specifically Mrs. Huff, since it will survive north Georgia winters) and many others.

For a more detailed list of butterfly plants, link to the FAQ section on this forum. Your relative can check with various sources to see if a given plant is native to or will thrive in the Atlanta area.

A good butterfly field guide, like Butterflies of North America by Jim P. Brock and Kenn Kaufman would show which butterflies occur there.

The best way to start would be for your relative to see a butterfly in the Atlanta area, ID it with the field guide, find out what the host plants are, and then consider planting that.

Good luck!

Sherry

Hey speyeria!
I live in North Georgia, but I used to live SW of Atlanta in Newnan, GA. misssherry is a very smart cookie and always gives good advice. I can tell you that there are a lot of deer down there, and they will eat most everything that you plant in the yard. Would be good to know if this is a wooded lot. Lantana grew very well for me there, and the deer left it alone. The natural soil is like concrete, and I often had to use a pick axe in order to plant something substantial. There is LOTS of Crape Myrtle growing down there, but it doesn't seem to attract butterflies at all. There is a nice natives nursery down there in Fayetteville, GA. Maybe he could contact someone there, and they could give him some good ideas. They are very friendly, and would be happy to speak with him. Hope that helps a bit.~~Angie
http://www.nearlynativenursery.com/