Oil-Pulling helps most people with sinus problems, it makes breathing really clear. But do keep in mind that just like #21277 said, if she has any root canals on the upper teeth this can very well contribute to sinus infections. I know because I have one that needs to be removed and I am having sinus problems because of it.
Candida fungus can also cause sinus problems. Does your wife have any reoccurring vaginal yeast infections? If so she may possibly have systemic candida which also can cause sinus problems.