My AH has .or was always a very honest person. One of the things I respected about him the most. With the progression of the disease, I have seen that change. The lying seems to be progressive,too. Maybe because his behavior is getting nuttier and he is trying to cover it. I swear, he may actually believe his own stories after he says them. Very sad.
He also has blackouts, I am now sure. I think sometimes he tries to "cover" for that time he can not remember instead of admitting he has no idea. That must be very frightening.