O'Shaughnessey

Bobby Mahoney awoke one morning to find a leprechaun sitting on his bedpost.
And so begins the adventure. The leprechaun is called O'Shaughnessey because that's the name the little fellow's chosen for himself and because his faerie name is virtually unpronounceable by humans. Bobby flies in the leprechaun's magical tricorn hat into the deep woods to meet the crusty, antisocial O'Sullivan with his hoard of gold, to the Cave where the Ban-Shees dwell, and to the Mountain of Shadows, where is kept the dreaded Coach-a-Bower, the Deathcoach. Author Jeremy McGuire weaves the invisible realms seamlessly with Bobby's real world where he experiences the divorce of his parents, and the illness of his little sister, each world influencing and being influenced by the other.
Is O'Shaughnessey real or an imaginary friend?
Yes.