Hello Trees and fellow Chatters. I've just returned from three days in Oxfordshire where I was gathering information regarding ETO's ancestors. He's descended from the Oxfordshire branch of the Osbaldestons who first appear in the records in Lancashire in the 12th century.
In answer to your question, ETO's older brother Frederick Turner married his first cousin Frances Maria Turner, daughter of Charles Pye Turner [junior] and Maria Lewington Turner.
His 1871 census return lists Frederick Turner, widower, 36, living with his son Frederick, 8; his sister [should be half-sister] Maria Turner [should be Osbaldeston], unmarried, 40, born in Woodstock, Oxfordshire; and his niece [should be cousin] Frances Turner, unmarried, 18, born in Reading, Berkshire. His occupation is listed as “Volunteer Adjutant.”
Regarding the newspaper articles about the man who went to South America to serve as a medical guinea pig, I suspect that ETO invented the whole thing to get his name in the papers. What makes me think so is the fact that ETO calls the man Ferdinand Pietrich. However that was the name of the owner of the Turkish baths in Melbourne where ETO worked in 1866!