What Causes Compulsive Lying Disorder In Person With Childhood Trauma?

Hi, my partner said he had a car accident years before I met him & has a metal plate in the back of his head, which gives him terrible headaches he says, especially when there s a big change in the temperature or when having been in an aeroplane. He was in a coma & in hospital for 9 months after his accident, learning to do everything again. He had a severely traumatic childhood was beaten by his father & molested by his father s friends. I ve noticed that there s always some drama in his life & have caught him out telling lies & being deceitful. His cousins say the same thing, so it s not just to me. The latest is he s taken off with barely any communication & has beenaway for nearly a month. He said he was going to the UK but I subsequently found out he never left the Country. I don t know where he is & when I ask him questions he either doesn t answer those questions or answers the questions he prefers to answer or lies. I ve told him I know he s been lying to me (when we ve communicated via email) but he is evasive & doesn t acknowledge what I m saying, as if he doesn t get it, but I m sure he does. Almost as if he s dissociated from what I m saying &even somewhat dilusional. I don t know what is wrong with him, if he s a pathological liar or what but there s definitely something not right with him. I know you can t make a diagnosis like this (although I wish you could). I was wondering if his strange behaviour is related to his childhood trauma or if it could be from his brain injury. He s not aggressive. I love him very much & would like to be able to help him if I can but am at my wits end. I feel like I m on a horrible roller coaster ride!