Some of his predictions were based on standard Medieval astrological theory and some were based on his own keen insight into the politics of his day. All of his predictions were clothed in vague and ambiguous imagery that is open to multiple interpretations.
His stuff was so vague,even for his time, that you can interpret them for almost anything. Add the fact that some of the writings were just made up by someone else and tacked on later, then the whole things come into question. So no, his predictions are just BS