We are first introduced to Almanzo’s brother Royal as well as Royal’s two sons Rupert and Myron, in the episode The Nephews in season seven. The two boys are wild and unruly, and are sent to Walnut Grove to stay with Laura and Almanzo. Royal was played by Woody Eney.
Two seasons later, in the episodes Times Are Changing Part One and Times Are Changing Part Two, Royal Wilder appears again (played by Nicholas Pryor this time) but the sons are nowhere to be seen. So what happened to the two boys Rupert and Myron?
This is one of the many plot holes that are unexplained in the television show – the boys are not mentioned again, not even a passing mention about them being grown up and living on their own. They simply vanish.
This is likely due to the plot changes within the show. Two seasons earlier, it wouldn’t have been planned out so far in advance where they would want to have Royal actually have a daughter instead of two sons, since that daughter Jenny would then come to live with Laura and Almanzo in season 9.
The real life Almanzo did have other siblings, so it is unclear why they didn’t utilize another sibling within the context of the show, other than they had previously introduced Royal Wilder in the show, and Royal ultimately has a significant role in the Little House on the Prairie books which the show is based on.
For more on the real life Royal Wilder, you can find Royal Wilder’s biography here.