OK, I found Bertha - the LA Secretary of State has some death records online - it says through 1956, but apparently they have added more.
Kinder, Bertha Currie, died April 26, 1960, Bienville Parish, Page 652, Volume 5 (you can order death record)
I did not find Minnie, so she may have died later and this site does not have a record. There was a Minnie Bell Gresham Currie, but I didn't think that was her.
Here's the URL: www.sos.la.gov/tabid