The things I would suggest are to have her get her vitamin D3 levels tested and then to supplement to the upper half of normal with a good quality oil based D3. The second thing is to buy some raw local honey and have some every day. Finally - does she do sinus rinses? Regular use of saline sinus rinses can help some people.
Some people report improvement of seasonal allergies just from going primal - so that may help her by itself.