Generally, it is not love it is curiosity that keeps a guy interested. Trust me if the girl says "yes" then it is likely that the guy will feel he can do better and lose interest in girl that said "yes". A man gets intense emotions quickly and then lose them quickly as well. That is why men are quick to get angry and jealous; and women do use this weakness very well in relationships.@Big Daddy: I agree with the points you have stated. However, I would still believe that the guy should give atleast one shy again at the girl, even if not to continue any further, but quite simply to hear from the horse's mouth on what actually transpired between the girl and her parents. If the girl was wanting to get into the marriage, but backed off simply because her parents decided against it, then the guy should not persue any further. We are making assumptions here, but no one knows for sure on what happened, not even the guy.
In my experience, a woman's decision making is less individualistic and more collective. What I mean by that is, if a woman really likes you, you will not be first to know. It will be her friends that will know first and confirm that it was a good decision and then you will know. So even if the guy tries to ask the girl he will most likely not get an answer. Why would she explain the collective decision-making process to a stranger or mere acquaintance that she will never see again?
The mistake we guys make is assume that girl is incharge of her decision-making. So, all those "no" changing to "yes" that you referred to earlier is mostly change in the "collective advisory committee's" decision. There are few women who take independent decisions but they are often considered as rebels or independent head strong women. Men sometimes get scared of such women due to lack of femininity.
The primary problem in this case distance. The guy does not want to marry for a year and continue a long-distance relationship for a year. What woman would find that desirable? The situation has a big "no" written on it. It is better to cut it off. Why put the woman on spot and seek explanation?