I’m sure they’ve read it, but Hatchet is a great survival story (albeit modern) if they like that aspect of pioneer stories.
It’s true, though, all the really famous pioneer kid’s books are about girls. Although there’s no reason a boy can’t enjoy Caddie Woodlawn and Sarah, Plain and Tall.
How about The Great Brain and sequels? They’re not really pioneer, but they’re historical - they’re set in Utah at the very end of the 19th century, sort of Tom Sawyer stories loosely based on the author’s childhood with his devious brother. They’re excellent, I’ve just started rereading them because I only vaugely remembered them from childhood. There’s a lot in there that gives it extra meaning now that I’m an adult.