Yes, January described what a neti pot is.
It is basically a little teapot (I like the one called Sinucleanse) which was designed by an ear, nose and throat doctor. Like Jan said, you tilt your head to one side over the sink and insert the spout into your nostril.(Both sides, one at a time) The warm salt water in the pot flows over your sinuses and out the other nostril. I know, it sounds very uncomfortable, and the first time I tried, it felt very strange. It gets easier each time though, and it's kind of comforting after a while. Unfortunately because I have inner ear problems, I do not use it as often as I would like to. But it does work, it's been around since ancient times, and the thing I did love about it was I could breathe at last! It clears up the post nasal drip also, since it cleanses the back of your sinuses as well. You can go to the sinucleanse website, it has a demonstration and everything. Of course, it's not for everyone, but it has helped, and the thing I like about it is it's medication free.
I hope you find something that will make your son feel better, Sabrina! There are all kinds of things out there, just a matter of finding something that works.
Best Wishes,
Zen