Sadly for Becca Butcher, she's just the type of character who was always meant to die. We never learned how she felt about being raped by Homelander and forced to run away from her husband and family to bear and then raise Homelander's child. Her very existence on the show was to serve as motivation for Billy's crusade and, later, for her son's power activation. She's never really been her own person on the show, and it's par for the course that her dying words aren't even about herself, but her son.
After Homelander and Stormfront take Ryan away from the compound, Becca is emotionally distraught. Billy returns to help reunite the mother and son, leading the Boys into a plan to lure Vought agents to Homelander's cabin as a distraction, and allow Becca and Ryan to escape. Billy was originally planning to let Vought agents separate Ryan from his mother, but undergoes a change of heart in the end, asking Mother's Milk to get the mother and son to safety without him. But they're confronted by Stormfront mid-escape, who is eventually able to corner Becca and begins to choke her out. Terrified for his mother, Ryan blasts at the two with his laser vision, incapacitating the Supe and fatally wounding his mother. She spends her final breaths forcing Billy to promise her that he'll protect Ryan and ensure her son knows that it's not his fault she died.
