My brother has been an International chess master for years but he can't seem to go any further?

He needs a combination of study and practice in strong events. He also needs the free time and that is the killer. Jacob Aagaard is an IM gone GM and has a series of great books that are useful. He will need to play in events where he can play GMs and might want to look into the US teams that play intercity matches or cheap foreign events where he won't be wasting his time playing player rated under 2200. Check THE WEEK IN CHESS web page.

If he has a job then he wont become a gm. As it takes hours and hours of your day to study to become a GM. To become a GM you need to get Norms. Norms can only be won in special tournaments that must be 9 rounds. The players there must be very high rated like GM and IM only. These are Fide rated tournaments not USCF and since he is a IM then he must have one. These are play mostly out of the country.

If he or you have the money hire a grandmaster rated at least 2600 and in person or internet do lessons.Try to go out side of usa to fine one.Those would be my thought on the question.

International in the US? When going from Boston to NY is like from London to Berlin and Boston to SD in longer than Scotland to Greece, the only FIDE tournaments in North America I ever heard of are some NY opens.