How does Robert Ruark use imagery in The Old Man and the Boy?

Bobby says that he knows that Mr. Howard's house remains in his memory, just as it was when he and the Old Man visited it. In his memory, the dream house never rots, never has pipes burst, never has a mortgage, and is never repossessed by the bank. He does not clarify whether or not these things really happened, or whether he is just referring to the fact that all things get old and pass away. This imagery is a metaphor for the Old Man dying. Bobby and the Old Man both seem to know that it is the Old Man's last autumn, and they try to cherish the time, even though the doctor has not yet given the diagnosis.