Godfrey's position in society used to be that of the promising heir to a vast property. People viewed her as an extension of his own father. He was tall, handsome, amiable, and seemed truly interested in the well-being of his father's estate. This is, of course, because people could compare him to his youngest brother, Dunsey, who was the epitome of irresponsible behavior, was rude, double-dealing, a drunk, a gambler, and an unreliable idle man.
The problem is that money was dwindling, and Godfrey did little to make any changes. Instead he showed his true weaknesses by following his brother's bad steps, by marrying an opium addict secretly, by having a child with her, and by allowing Dunsey's double dealing to ruin him and leave him without money.
Therefore, people were seeing these things taking place and slowly began to change their opinion of the righteousness of the heir to Cass. This is how his position began to change.