Switch and Switch Again

Charlie walks into the hospital room to see his great nephew Sammy.  He is concerned about him since Sammy tried to commit suicide a few days before.  He hadn't seen Sammy since he grew up.  Sammy tricks him into switching bodies with him; Sammy wants to get Charlie's retirement income and never have to work.  Charlie accepts being young again and decides to go to college and get a degree.  He finds a place to live and gets involved with a young woman.  The problem was he was afraid he might switch back to his old body.  Meanwhile his great nephew has married a rich widow and is enjoying living the life of leisure.
This story has some explicit love scenes so is for mature readers.