Curious if it is halachically allowed, due to the first part in your post. Being that א"ר יצחק צדקה עשה הקב"ה עם ישראל בשמשפחה שנטמעה נטמעה:
I once heard a story from someone in Crown Heights who told me that there was a certain B.T. who used to be a regular guest in their house (if I recall correctly, this was actually when they lived OOT) and was an outstanding person, extremely talented and sincere in Yiddishkeit. Unfortunately, at a certain point that person's mother disclosed to him that he was born from an extra-marital affair. He felt like his life was shattered, and IINM fell into depression and left everything.
When the person who told me the story went to consult with R Z.S. Dworkin about the situation, R' Z.S.'s response was: זי איז ניט באגלייבט, ער איז א כשר׳ע איד! But unfortunately said person was too broken from the situation, and didn't want to come back.