Yes, I've recently had great success extending time between clusters, reducing the severity of attacks and reducing the length of the cycle. And all of the success came from visiting online forums with fellow sufferers. All of the doctors I saw over the 30 years i have dealing with it have not helped at all.
If your brother has not tried it yet, hyperventilating pure oxygen is the most helpful tool in the arsenal. My doc couldn't get me a script so i use welding O2. I can't discuss in this forum the other alt therapies, but he could PM me or he should at least visit clusterbusters.com
It is very common for sufferers to have clusters less frequently but with more intensity as they get older.