The Ghost Buddy Series
by Henry Winkler (Author) Lin Oliver (Author)
This could be a match made in Heaven because, while Billy is dealing with a lot of uncertainty about his new life, Hoover Portherhouse (aka the Hoove) is a ghost with all the answers. Billy soon discovers that having a ghost around might not be so bad after all. The Hoove is funny and cool, a great baseball player and a real people person (even if Billy is the only one who can see him).