Roderick Usher has several character traits.
The first is that he is isolated but still yearns for human contact. He and the narrator have been friends since they were boys. The narrator is his only remaining friend.
The second is the reason the narrator is coming to visit: Roderick is ill. He's suffering both physically and mentally.
The third is that he is reserved. He's been reserved since he was a boy.
A fourth is that Roderick, like the rest of his family, cares deeply about the arts.
A fifth is that he, again like the rest of the family, engages in considerable charity.
All of these we're told directly. From the condition of the Usher family home--in great decay--we can conclude one more important one. Roderick isn't strong enough to maintain his family home.