Caution: The following contains major SPOILERS for The Boys comic book series that may or may not play out in future episodes of the TV series. Proceed at your own caution.
Billy Butcher's death could give The Boys a happy ending if the show changes how and why it happens. Amazon Prime Video's hit superhero satire is an adaptation of Garth Ennis and Darick Robertson's comic run of the same name. However, Eric Kripke's show is not afraid to make changes to The Boys' source material when needed. It is still committed to bringing the overall ideas of the comic to life, even if it alters the paths that The Boys, The Seven, and other characters take. While The Boys season 3 won't be the end of the story, there are already questions about how the series' conclusion will compare to the comics.
The end of Ennis' The Boys comic story included the death of Billy Butcher, who Karl Urban plays in the series. This came after a Supe killed his dog and drove him mad with revenge. Butcher decides that his best course of action is to use deadly chemical weapons to target people who are genetically more likely to develop superpowers. When The Boys attempt to stop him, Billy kills Mother's Milk, Frenchie, and The Female. However, Hughie Campbell manages to kill Butcher before the chemical weapons are put to use. The Boys can't use this comic ending without betraying many parts of the show's story and characters, but that doesn't mean Billy's fate is safe.
Based on the number of deaths that The Boys includes and its overall pessimistic worldview, most will expect Amazon's superhero show to go out with a bang. The idea of Billy Butcher dying seems almost too bleak of an ending for the show considering how prominent of a role he has, and the majority of viewers would surely be upset if it came at Hughie's hands. However, The Boys could flip the meaning of Butcher's death. He may have already lost his wife Becca, but his unofficial son Ryan is still out there. Butcher could die protecting him and the memory of Becca. It would certainly be a heartbreaking way for Billy's story to end, but The Boys could also see Hughie and Starlight agree to take care of Ryan. This would fix how Hughie and Butcher's relationship ends and give the show a slightly more happy ending for at least a few of the characters.
Billy Butcher and Ryan might not be biologically related, but The Boys season 2 went out of its way to show them bond. Butcher consoled Ryan after Becca's death and decided that it would be in the kid's best interest to go with Grace Mallory and the CIA to be protected from Homelander. It is expected that The Boys season 3 will continue to strengthen the bond between them in some fashion. Since Billy is the only one who Ryan really cares about anymore, his death would surely hit the young Supe hard. Butcher dying in the same fashion as the comics would likely mean Ryan becoming evil like Homelander, but The Boys can prevent that by having Hughie and Starlight take the kid under their guidance.
Hughie and Starlight deciding to help raise Ryan in the aftermath of Butcher's death can allow The Boys to end on a happier note. The show can thematically conclude with a tease that the next generation of Supes could be better off than what came before as long as they have the right people caring for them. This would likely mean that The Boys' series ending also needs to include Vought's collapse, as their superhero and Compound V empire still reigning would contradict that idea. As a result, it is possible that Billy Butcher's death could come as he finally achieves his goal of taking down Vought and The Seven, giving Hughie, Starlight, and Ryan a chance at a fresh start.