To what I remember, he works on the base of the skull, and sometimes a bit higher, so the whole skull moves properly. Might sound impressive, but it's not at all.
I just wished I started earlier with my son when he was a baby, as I have spent some time at the hospital with him, or waking up 20 times a night to make sure he was breathing properly.
Medicines will help release the symptoms, but they don't stop the problem.