You bet he knew zero. Times were very hush hush then and having an older sister who was already a “fallen girl” after 3 out of wedlock pregnancies from 3 different men over few years who was just trying to repair her reputation by marrying the man who fathered her last child (not JAZ, his younger half sibling) while married to someone else - you bet she did not share much about her past. Also I believe this brother was much younger than her. He possibly only knew his sister was married and had several kids and never knew she had children before that marriage who „disappeared“. Her first out of wedlock baby also was never accounted for, supposedly it was adopted out but noone really knew details.The maternal uncle was still alive at the time of identification. I still wonder what he knew and what he could tell police.
jmoo