Looking for Oscar Wilson

He is my grandfather. He died in New York City in about July 1935. My mother was 9 months old. He was married to my grandmother Edna Riggs Grant. He was born in Norway and after his death my grandmother sent a letter to Norway to his mother telling her that he had died. I have this letter. It was translated that same year but they didnt give me her full name. If I post the letter on here can someone help me with the her last name?