But I can tell you that A C Kastner was married to Minnie Adelade Chastain and that they were living in Barton County Missouri when Minnie Adelade 'Addie' Kastner died in 1950.As is indicated on her death certificate.
Addie was buried - by herself - at Wise Hill Cemetery in Clever, Christian County, Missouri with the rest of her family.
I can't say for certain that this A C Castner is Antone Conrad Kastner.However, it's a rather unusual surname for that time and place so I have to wonder if this wasn't him.
I can tell you for sure that Antone Conrad Kastner was born in Festus Missouri and lived in Monterey California for quite a while - based on WWI draft registration and voter registration records.
Let me know if you turn anything up - I would be interested to learn more.