Tony's (Avengers: Endgame, which wrapped up the Infinity Saga with the defeat of Thanos (Josh Brolin). Endgame also marked the final chapter for some of the MCU's founding heroes, including its very first one - Iron Man.
Chris Evans) are forced to improvise and make the jump further back to the '70s to steal the Tesseract. There, Tony encounters his father just before his birth, giving him the chance to come to with his issues with Howard.
Tony had a difficult relationship with his dad. He described the older Stark to Nick Fury (Samuel L. Jackson) inthey were brutally murdered by the Winter Soldier (Sebastian Stan). Tony's time travel encounter with his father helped wrap up the character's MCU journey before his sacrificial death at the end of Avengers: Endgame. Aside from that, it's also a motivating factor for his final heroic act.
Based on Tony's recollection of his dad, Howard was never really around. Endgame reinforces this idea by showing the older Stark still spending time at work despite his wife's impending labor. While a younger Tony would've been more resentful of his father for this, he's surprisingly understanding because at that point, he personally knows what it's like to be in his old man's shoes. His stint as a superhero better informed him about his father's contributions in safeguarding humanity with Howard's involvement in the creation of S.H.I.E.L.D. and the Super Soldier Program among others. This helped Tony realize that the reason why his dad wasn't around his family was because he was busy contributing to society, and Tony sees himself in his father.
Before Thanos' arrival, Tony was consumed by work, determined to ensure that Earth was better prepared for another alien invasion similar to the Battle of New York in The Avengers. When they lost in Infinity War, his worst nightmare came, but the tragedy gave him the opportunity to focus on his personal life leading to his five blissful years with his own family. Tony's realization that he mirrors his father in this regard makes it easier for him to don the Infinity Gauntlet later on in the film despite knowing that it will kill him, effectively widowing Pepper and orphaning Morgan. He banks on the idea that if he could forgive Howard for prioritizing the greater good over his family, Morgan could eventually forgive him as well.
Tony's encounter with Howard also explains his odd conversation with grown-up Morgan (Katherine Langford) in the deleted Avengers: Endgame Soul World scene. Afraid that his daughter would resent him the same way he did his father, Tony rambles about second-guessing whether or not he made the right decision to sacrifice himself to defeat Thanos. Morgan assures him that his sacrifice paid off as it allowed her to grow up in a safe world. In the end, she quells his fears of leaving her and tells him it's okay to go.
