User blog comment:B214/Question and Answers 2/@comment-24098614-20140228160822

I think B214 is right about Issei not divulging the information because Issei wouldn't be able to live with himself if something happened to his parents, and it was his fault but the problem is that this secret will come whether Issei likes it or not because some important event in the story will take place that will tell his parents the truth about him so Issei himself will not be the cause of this or it will be one of his enemies that does that for him.