What is the current Receiver (old man) like in The Giver?

You've correctly identified one characteristic about the Giver.  He is an old man.  Jonas is the second receiver of memory to work with the Giver, and new receivers are chosen in order to ensure all of the knowledge can be successfully passed on.  The fact that the Giver is on his second receiver of memory definitely means that he is getting old enough to start worrying about his life span. 

The Giver is also kind and patient.  He is not easily angered either.  Because he is a giver, he is blessed with more knowledge and learning than any other person in the entire community.  He is in charge of storing all of the past's knowledge and feelings.  Perhaps as a result of that, the Giver is also a rather cynical character.  He believes that the society he lives in is not as good as it could be.  He sees the Sameness as more hurtful than beneficial.  I believe that as a result of his cynicism, the Giver intentionally distances himself from everybody.  He lives a fairly secluded life and doesn't socially interact with anybody unless he absolutely must.