Melissa Gilbert who played Laura Ingalls on the show, and Jonathan Gilbert, who played Willie Oleson on the show, actually are real life siblings, although they were both adopted the same parents.
In later years, Melissa and Jonathan has been estranged. Melissa’s Memoir, she recounts how Jonathan has been estranged from their family for many years, and she does not know the reason for this is estrangement. Is unknown if Jonathan is just estranged from Melissa, or if it is from his entire adopted family.
Melissa still works in the industry, although Jonathan is no longer acting and is now working in finance.