Draco Malfoy didn't want anyone to know he went to Fred Weasley's funeral. He stood in the back as to make sure no one saw him. He felt horrible for being part of the reason he is dead. When everyone left he walked up to his coffin and cried. He didn't try and hold it back. He would never tell anyone he was there.
And George would never tell anyone he saw Draco crying at Fred's grave.