What if people know? This is one thing two partners who are in love and planning to marry should NOT be worried about. I do not see any reason to hide such a committed relationship from others. I think taking your parents into confidence was a good move from your side. Also you seem pretty clear about your expectations and are you clearly committed and love the man. I think you have done all you could to shape your relationship.
I am not sure if you are willing to wait after having waited so far for a period of 3 more years. There also seems a lack of clarity on your boyfriend’s part about the time-frame within which he should announce the relationship and convince his parents. At this point, you might want to clearly discuss his plans about your relationship face-to-face and understand his position. He maybe having plans that you might want to find out.
If such an interaction can take place, you might have a bit more clarity, once you have your doubts cleared with your loved one. Your confusion is obvious in the current situation. Once you have had such a discussion, it could be easier for your to decide the path forward, in my opinion. I hope all goes well for you.