These 'This Is Us' Theories Might Explain Kevin & Randall's Mysterious Feud

Kevin and Randall Pierson have never had the easiest relationship on This Is Us, but a recent flash-forward revealed that the brothers are no longer on speaking terms by their 40th birthday, which has left fans to wonder what the heck happened. Luckily, there are a few This Is Us theories about Kevin and Randall's feud that have come out of the woodwork since the midseason finale and may help to explain what caused the rift between these two siblings in the first place.

The flash-forward itself provides a few helpful clues on the matter. For starters, Kevin and Kate were celebrating their birthday together sans-Randall, indicating that neither member of the Pearson Big Three are currently on speaking terms with him. Therefore, whatever happened had to be pretty huge to cause such a prominent family divide. The scene also confirmed that Rebecca's memory is still continuing to fade. When she was brought back to Kevin's place by the police after getting lost, she asked if Randall was there yet, to which Kevin responded: "No, Mom. Randall's not coming. We're not speaking, remember?"

No other details about the feud were given, but that hasn't stopped viewers from theorizing every possible scenario out there to help explain this heartbreaking fallout.

1. It Involves Rebecca's Deteriorating Health

During the present day Thanksgiving episode, Randall was the only one aware that Rebecca is starting to suffer from memory issues — something that she urges him to keep a secret from his other siblings. Reddit user annist0910 predicts that could be the driving cause as to why Kate and Kevin are upset with Randall — because "he knew she had dementia and didn’t tell them." It's definitely the most logical answer, given the sensitive subject matter. Even series creator Dan Fogelman told People that the theory is “definitely a possibility of the right area.” Though, perhaps that makes it the most unlikely scenario, given the show's reputation of delivering unexpected twists.

2. The Fight Involves Tess

Reddit user grania17 suggests that the rift doesn't actually have anything to do with Randall and Kevin at all and actually centers around Tess. "Maybe in Rebecca's memory hell she lashes out at Tess and says something horrible about her being gay and that is why we see Tess very hesitant to visit her in the future and why Randall and Kevin/Rebecca don't speak," the Redditor explained. The theorist added that maybe Kevin plays it off as being a symptom of her illness, whereas Tess and Randall would take it to heart.

The flash-forward doesn't make it clear who exactly is mad at who. Is Kevin mad at Randall or vice-versa? Is Rebecca mad at Randall? Is he mad at her? It definitely opens up a wide range of possibilities, making this theory all the more plausible.

3. It Concerns Kevin's Pending Nuptials

It's also just as likely that this feud has nothing to do with the Pearson matriarch at all. Maybe Randall doesn't like Kevin's fiancée for some reason and it causes a divide. Kevin has been wanting a family for a while now, so if his brother were to threaten that in some way, it would make sense for him to get defensive about it.

4. Rebecca Is The One Upset With Randall

Meanwhile, Reddit user yesitsmenotyou believes that the feud is actually between Rebecca and Randall. Viewers already saw the two of them get into a small spat when the subject of Rebecca's memory was first broached. If Randall continues to push her to get treatment too hard, too fast and she doesn't agree with it, it could lead to some huge ramifications within their relationship. If that's the case, then perhaps Kevin and Kate are only pretending to be mad at Randall as well so that she doesn't feel completely abandoned by her children.

All of these are sad outcomes to consider, but then again, heartbreak is what this show does best.