That doesn't seem too weird to me. My brother's mail ends up here sometimes, and he hasn't lived here for five years. My late stepfather's nephew? Cousin? IDK. He lived here briefly on a work stay over a decade ago, and we still get his superannuation statements.
Of course, he could have had them sent to her house if he knew that the contents would be an issue with his parents. He had a sex doll, right? I assume it was an adult one. Child sex dolls are illegal, in my country, anyway... Every few years, some creeper is on the news getting arrested here for trying to import one.
MOO