While the contention is feasible, it constitutes a prediction. It is not an argument well suited to this format due to the vast number of factors involved.
Most minorities are more familiar with Hillary Clinton right now than Sanders. Once he wins a state or two, his profile would rise, and he would do better. He has a very good civil rights record.
Bernie Sanders has pulled enormous crowds filled with young voters, unlike before. At best it is inconclusive if young voters will actually participate.
Even if a large portion of young voters turned out, it would be difficult to overcome the establishment. Numbers I saw recently were ~40% young participation and ~20% for the rest of the electorate for him to win. While not impossible, these are not likely.