Various psychologists have speculated for several years about possible ways to define what he shows in his continuous mental quirks.
He seems to combine narcissism, amorality, aggression, obsession, greed.. and several others in odd combinations.

His niece, Mary, laid it out pretty well in her book and various interviews. Whatever you call it/them, the practical result of his 'inaccurate statements', whether he KNOWS they are lies or not, it that everyone of them requires more of them. There's no way to get out of the hole has dug for himself and others he has dragged down with him.
There's no doubt he is technically guilty of various crimes.. the only question left is whether it is worth the trouble to investigate, indict and prosecute them, knowing how long it would take and the resultant obsession in the news while we need to concentrate on the NEXT 4 years.