"Is he related to Rod?" and other writers overshadowed by more famous siblings

Robert J. Serling, still alive at age 91, is a darn good writer (novels, nonfiction), usually within the aviation field. But his younger brother of course created “The Twilight Zone,” and will metaphorically live forever because of it.

Any other writers who deserve more than to be known as “So and so’s brother (or sister)”?

Sir Rhosis

Jack C. Haldeman II (brother of Joe)

Frederick Barthelme has always been overshadowed by his brother Donald. Personally, I prefer Frederick’s work. Less flashy, less likely to be taught in an MFA program. He does have a tendency to write the same novel over and over again, but at least it’s a good novel.

My father was a fan of both, but he also never heard of an air crash he didn’t want to check out.

Anne Brontë.
Also - she’s not a sibling, but how about Tabitha King (Steven’s wife)

Michael Penn/Sean Penn.

Technically fits…Michael writes music, OP doesn’t specify elder has to be famous in same field (or in writing).

His biggest hit:

One of my faves:

William Faulkner’s brother John

He’s not famous yet, but it looks like Stephen King’s son Joe (Joe Hill) is (so far) doing better than his brother Owen. Heart-Shaped Box is gonna be a movie, and Hill’s second novel is due out soon.