According to you, Andres had no agency to not get together with Emily. She FORCED him to raise the child, when in actuality it was his choice to give her the ultimatum to never contact Santi and raise the kid as his.
In regards to Santi not being there or doing enough, he had left school by the time Emily gave birth and she didn't see him for 12 years. When MC asked if Santi wanted to meet him, he did but Andres' made it difficult.
All this drama would have been avoided if Andres wasn't a megalomaniacal asshole, who insisted that he had to date Emily and that she wasn't allowed to communicate with her son's actual father.