I don't think he will retire just yet. I can see that he still feels like a young boxer even today and even had the guts to challenge Moloney for the WBC title. But I guess both boxers are trying to go the easy way to take the belt. Moloney dodges the fight or it's Donaire, it doesn't matter but I do believe these two will try to meet to unite the belts.
We are speculating again, of course. He will not retire, as he has not mentioned retirement yet. Though his age is considered old but the way he fights shows he still has the heart of a champion. His upcoming fight will prove the doubters wrong. It may not be against a major challenger, but a good win will always attract the attention of the crowd.
There aren't many doubters here for Donaire; in fact, I believe that the majority of us are counting on him to beat Santiago. If he were up against Moloney, the challenge might be tougher, but in this case, Donaire is listed as the favorite to win, so he is likely to emerge victorious.
Therefore, I'm optimistic that he'll win via knockout.
That's what everyone is expecting, as Donaire is known to be a knockout artist. If he can't KO Santiago, then he'll be in trouble and might lose on the judges' scorecards.