Fred is Scrooge's nephew. He is characterised as Scrooge's foil, as, unlike Scrooge, he has little care about the wealth of others, is very fond of the Christmas spirit, and interacts positively with people he meets. Despite Scrooge's personality, he still invites him to dinner with the rest of Scrooge's family, emphasizing his philanthropic nature.
Fred symbolises two of the main themes in A Christmas Carol - family and Christmas Spirit. Despite Scrooge's dislike of his presence, he still wishes him Merry Christmas and invited him to his dinner, emphasized the strength of family bonds. He also has a wonderful time with his family at the dinner - they played games and had a wonderful dinner. He is also symbolic of the Christmas spirit due to how he brings charm to everyone.
Quotes said by or that describe Fred that you may find useful:
"He had so heated himself with rapid walking in the fog and frost, this nephew of Scrooge's, that he was all in a glow; his face was ruddy and handsome; his eyes sparkled, and his breath smoked again."
"I have always thought of Christmas-time ... as a good time; a kind, forgiving, charitable, pleasant time..."