This is really good advice and has worked for us:
https://goqii.com/blog/foods-to-cure-sinus-infection/ Also, good health is not about being lucky as often as it is about the work one puts into being healthy.
We found our biggest enemies to be dairy (cheese and milk) and meats. Limiting both of those items to almost none really helped us avoid sinus infections. The other thing is not having the air too dry - humidify if in a dry climate.