The answer is, yes, macro would be useful to helping people with many different conditions including severe food allergies.
Do you have a copy of
The Macrobiotic Path to Total Health:A Complete Guide to Preventing and Relieving More Than 200 Chronic Conditions and Disorders Naturally by Michio Kushi and Alex Jack?
I recommend that you get a copy from this site's bookstore if you wish, from a local bookstore or natural bookstore if that works for you, or from your local public library.
The book deals quite thoroughly with the topic of allergies (amongst other conditions and disorders), especially food allergies, and you might get a good hand on how to approach this problem and how to communicate how macrobiotics could help Trace's child when you are communicating with him or his people.
How are your husband and your brother doing, now?
Thank you, very much.
Bruce Paine