Initially, it works to keep you in contact, but in reality, bringing up past positive times does not excuse bad behavior, especially if the good memories were way back in the past. This is purely manipulation and is a way to deflect attention from what they’re doing in the background. This is because a narcissistic family will use a smear campaign by getting to control others’ perception of you if they can’t control you. By bringing up ‘past good memories,’ it is a desperate attempt to get back into your life. I would also say that it is a very weak attempt because it is trying to play into your inner child by also reminding you of what they did for you when you were a young boy. This is not a good excuse at all because if this were the case, then every interaction that gets worse in different relationships would be ignored.
Son in the Shadows: "Navigating Life as the Black Sheep of Narcissistic Parents" 