This is odd! I did find an obituary for Rex Cantrell and it mentions his mother Bernice Cantrell and a brother Roy "Loe" Cantrell (could be a typo.)
Here's the link (and I attached it)
http://news.google.com/newspapers?nid=1346&dat=19950323&...It is very odd that he is not mentioned in Bernice Cantrell's obituary!
I guess it's POSSIBLE that there are two sets of Bernice Cantrells (with sons Roy), but that's VERY, VERY unlikely. It's more likely that whomever wrote Bernice Cantrell's obituary left him out.
Do you know if Thurman and Bernice lived in Haynesville, Louisiana at one point?