Is it possible for Dr Paul to win the GOP nomination through the process of a brokered convention? Here is a piece of US history that you should consider before answering: How Lincoln Won the 1860 Republican Nomination
It is possible, but not probable. 150 plus years has altered many mindsets. Lincoln would not have been able to do that today unless he had quite a bit of dirt on some heavy hitters.
Paul doesn't have that many friends who are Delegates, nor many who are Chairmen of the State Party. He may try, but he will fail.