Alejandro's real father (Possible Spoilers)

I started watching this novela towards the ending but got the gist of the story just fine. However, I am a bit baffled over the whereabouts of Alejandro's real father while Alejandro was growing up. Where was Nestor all this time? Did he know he had a son? Did he walk out on Alejandro and his mother?

(POSSIBLE SPOILERS!!!!!)





Also, I feel that the final episode was a bit sad. I did not think it was necessary for us to see how so many of them died. The death that saddened me the most was Constansio's. He looked neglected and broken. His house was also in need of repairs. He did not look like a man who had a family that loved him. Since his family forgave him, they should have shown him old but well taken care of. He did not portray the idea of a man who had a loving family watching over him in his old age. He looked as neglected as his mansion. Also, I didn't care to see how Alejandro and Mili died. The make-up was terrible. They should have used a real old man and woman to play thier parts. In my opinion it would have been even better if they had just shown their tombstones with the dates of their deaths to show us that they truly lived to be 90 years old. This is just my opinion. If you liked the way it ended, then that is just fine by me and respect your opinion. What I realy want is an answer to my question about Alejandro's real father. Thank you.