You can try the funeral home/cemetery that handled his arrangements to see if they have a copy of his discharge on file. Another avenue would be the local tax office or town clerk where he lived, many veterans files a copy of thier discharge for safekeeping and tax benefit purposes. He has a Veterans Affairs Death File, you can contact them to see if they have his information.
Here's his service number- 482465290
and his dates of service: 06 Nov 1952- 03 Nov 1954