Whether you do or don't like Charles is not the point. People will persist in believing that his "real" name is Charles, ask for proof that it isn't, forget they asked and ask again and so on and on ... what is so bad about naming him Charles and calling him Charlie?
Once I met a Chip who was the son of Chuck and the grandson of Charlie. All three of them were Charles on the documentation. I wish I knew what happened to Chip - did he ever marry? Did he have a son?