Will a pathological liar ever admit there wrong?

Just tell him to go to hell. Send him on his way because he's evil. Then you can find the kids a better dad who isn't full of crap. And if you don't then youre full of crap too. Otherwise you can take some abuse and abuse a little yourself tell him he's a wonderful dad but unlike you he's a terrible liar. You can't fix him he's damaged forvever.