In the book To Kill a Mockingbird, what was Boo Radley's childhood like?

Poor Boo (Arthur Radley)! He had a very dysfunctional
childhood. His father was a religious fanatic that was very severe with his son and kept
him a virtual prisoner in his own house. The rumor was that Boo eventually stabbed his
father with a scissors. And, when Old Mr. Radley died, Boo's brother came to live in the
house. The brother is the one who boarded up the tree to prevent Boo from leaving gifts
for Scout and Jem. He, too, seems severe and mean. As a result, Boo became a recluse. He
turned into a shy, but kind man, who watched out for Scout and Jem and eventually
protected them from being killed by Bob Ewell.

Read about
his character at the link below.