A Mourning of Remembrance by Stephen Tiedman

A Mourning of Remembrance is a touching story about Gavin Pierce, a slightly autistic young man, who makes a promise to his grandfather who has Alzheimer's.  When his grandfather wants to visit the place where he had his honeymoon to see what he can remember, Gavin takes it upon himself to get his grandfather there.  The promise places Gavin in situations well outside his comfort range and forces him to make a decision if he is going to fulfill his promise.