Born in Manhattan, New York 1st Lt Coiner entered the service in 1941. He was killed when a shell accidentally exploded next to him while serving in Australia. He was survived by his wife, a son and daughter, his mother and brother.
http://goldstarfamilyregistry.com/heroes/robert-coiner-186487
http://goldstarfamilyregistry.com/heroes/robert-coiner-186487 (pg 9)
https://www.oregondigital.org/catalog/oregondigital:fx71bn37g#page/8/mode/1up/search/coiner (pg 8)
https://www.oregondigital.org/catalog/oregondigital:fx71b965k#page/5/mode/1up/search/coiner (pg 5)
https://www.oregondigital.org/catalog/oregondigital:fx71bk76r#page/17/mode/1up/search/coiner (pg 11)
https://www.oregondigital.org/catalog/oregondigital:fx71b961g#page/5/mode/1up/search/coiner (pg 3)
https://www.oregondigital.org/catalog/oregondigital:fx71bk95z#page/6/mode/1up/search/coiner (pg 4)