It is difficult to answer the hypothetical nature of the question. Like Changez himself, the question is rooted in what could or what might be. One basic element that has to be addressed would be Changez's identity. The first would be that whether or not Erica could have been saved, the issue is that Changez needed to have a more solid notion of himself. In his relationship with Erica, Changez was not really in touch with a sense of identity that was permanent. True to his name, everything in Changez's life was immersed in "change." There might have been a different outcome with everything around Changez had there been a different and more stable sense of identity within Changez. Certainly, this argument lends credibility to the idea that had Changez been able to be there more from an emotional and psychological point of view for Erica, things might have been different.
At the same time, I think that Changez's own sense of questioning his identity made it difficult for him to help anyone. Since he was having difficulty helping himself, I think that he became relatively incapable of helping anyone else. Changez could only help Erica and others if he was able to help himself. It becomes clear with the massive level of changing and absorption of new ideas that begin to transform him that he is incapable of helping anyone. It is in this realm where one could make the case that had Changez had been less influenced by change and more convinced about his own identity, he might have been able to offer more to Erica in way of help.