Harry Sinclair
From Tardis Wiki, the free Doctor Who reference
Harry Sinclair was the older brother of Helen and George Sinclair. Helen found him difficult and patronising, leading George to incorrectly believe that she did not like him.
After Helen left to travel with the Eighth Doctor in 1963, the two siblings never saw one another again. He died of old age in the early 1990s, leaving behind a son who visited George with decreasing regularity. (AUDIO: Absent Friends)
