Trump appears to suffer from clinically diagnosable NPD

and he is not the only one among many historical system-shapers.  

The problem is that he lacks a single confidant—either within his family or among his political allies—who is able to help contain his larger-than-life ego within graceful boundaries, and to protect and present both himself and his agenda in a way that matches the intensity of the energy he pours into them.

This imbalance will backfire, sooner or later.