Joe blew Oliver's perception of these events to pieces with the revelation that he was born out of his mother's infidelity and not a direct O'Toole descendant, and that it was his mother who stopped sending postcards, not that Joe prevented her from being able to do so.
If we accept this narrative, then Oliver remembers these traumatic events, which have dictated his behavior towards his father. Joe's revelations, however, don't seem to really improve Oliver's relationship with his father much past the events of Truth Be Told.
We don't get a sense of this until One In A Million. When Joe and Oliver meet in the Mailbox Grille, it's clear they haven't connected much. The only reason they connect in this film is a function of necessity related to the letters taken hostage.
Joe describes Oliver was 8 when they took him hiking for the first time, the trip during which Oliver observes his parents fighting, prompted by his wandering. It's then 3 weeks later that Oliver's mom leaves them. Joe then makes the assertion that a part of Oliver has been blaming himself for his mother leaving, the complete opposite of the perspective we come away with after Truth Be Told. We also see Oliver putting the pieces together as his father tells the story, making the connection between his father purchasing the bird album and his fear of returning to the woods given what occurred between his parents in real time, as if he doesn't remember them.
To make things a bit more complicated, earlier on in Lost Without You, when Oliver is expressing his sadness over the death of Eleanor, Joe tells a story about how, upon hearing of his ex-wife's passing, goes to the mountains to watch the sunset. Oliver doesn't seem to recall this at all. Also, we get the sense that Oliver's mom became ill and passed quickly, because Joe states, "...I thought we all would see her again...but then she got sick and she was gone." In Truth Be Told, we get a sense it was several years before Oliver's mom died, and we aren't given the cause.
So now we have two realities. In the first reality, Oliver is 13, and has formed opinions about the state of the relationship between his parents such that he deems his father responsible for his mother leaving. In the second, Oliver is 8 years old, heartbroken by his parents unraveling, subconsciously finding himself responsible, but having blocked the event out for the most part as an adult.
The narrative that had Oliver blaming his father for his mother leaving, only to have that perspective flipped on its head, fit nicely within the events of Truth Be Told as a single film. We are presented with a father/son conflict that is soon eclipsed by Oliver's identity crisis. As questions about Oliver's identity are seemingly answered and reaffirmed, we think that perhaps Oliver's relationship with his father is also on track to be rectified given "the past does change after all." There's also the more practical reality that, from a casting perspective, it might not have been possible to lock in Gregory Harrison for more than one film in 2015, necessitating the story be open and shut in the course of a single film, while leaving the door open for Papa O'Toole to return.
In 2016, we knew we had Gregory Harrison for the long haul. The reconfigured story here facilitates a larger arc of growth for Oliver overall. Having Papa O'Toole around---the "Senior Expeditor" he is---for more than one film allowed a greater exploration of Oliver's past and its impact on his present. We also get a glimpse into the state of Joe's heart as well. It becomes clear that both men have wounds that need healed.
Whichever story you choose, what doesn't change is the impact of these emotional wounds suffered by the O'Toole men on the state of their hearts decades later, and it's this narrative with which our time and attention are best spent. You'll get a sense of this tomorrow as we start digging into Papa O'Toole and the state of his heart.