Please see the satire below

Please see the satire below. It is located on page 42 and is titled "The Passing of Grandison". I am a little confused and need help explaining 1) How humor plays a role in the story? 2) What other meaning might "passing" take on in this tale as it refers to Grandison? What does he try to pass himself off as?

Please see the following reference:
"Week Two: Freedom and the Gilded Age" Hardcopy: American Literature Since the Civil War. Create edition. McGraw-Hill, 2011.
ISBN-10: 1121233104 ISBN-13: 9781121233102