This is a good question. A few preliminary comments might be helpful. Oedipus at Colonus was probably written around 406 B.C. This means that this is one of the last tragedies of the great Sophocles. This also means that it was finished after the Peloponnesian War, which decimated Athens. In a word, it was written in a time of suffering.
From this persepctive, the character of Oedipus can be understood a little better. Oedipus, like Athens has grown wiser through suffering. So, although he is now blind, he is characterized as a wiser person. This is in stark contrast to his brashness and arrogance in Oedipus the King. We can say in a figurative sense he was once blind and now he sees.
Second, Oedipus also accepts his lot. There is little striving to outwit or outsmart the gods. In fact, he is sitting for most of the play; there is very little action. He realizes that the prophecies of the gods are true. In fact, he begins to realize that the is at the right place at Colonus.
Third, he is a person with great mystical power. In a sense he is sacred. He dies offstage and he becomes a blessing to Athens.
Finally, he is characterized as finding a home and coming to rest.