According to his grave marker he was a WWII veteran, Co 14 Armored Div.According to the Find A Grave site, he was the son of Arthur & Lucy May Day.
This may be Arthur Abraham in 1920:
1920 United States Federal Census about Abraham Day Name: Abraham Day [Abraham Doy] Age: 16 Birth Year: abt 1904 Birthplace: Utah Home in 1920: St Anthony, Fremont, Idaho Race: White Gender: Male Relation to Head of House: Son Marital Status: Single Father's Name: Arthur Day Father's Birthplace: Utah Mother's Name: Lucy Day Mother's Birthplace: Utah Able to read: Yes Able to Write: Yes Household Members: Name Age Arthur Day 40b. 1880 Utah, parents b. Utah; retired farmer Lucy Day 37 -wife- b. 1883 Utah, fath b. Scotland, moth b. Wales Abraham Day 16 -son- b. 1904 Utah ** Iris Day 14 -dau- b. 1906 Utah Willis Day 12 -son- b. 1908 Utah Clifford Day7-son- b. 1913 Utah Ursla Day 5-dau- b. 1915 Utah
This might be Arthur in 1930:
1930 United States Federal Census about Arthur A Day Name: Arthur A Day Gender: Male Birth Year: abt 1904 Birthplace: Utah Race: White Home in 1930: Midway, Canyon, Idaho View Map Marital Status: Married Relation to Head of House: Head Spouse's Name: Aileen Day Father's Birthplace: Utah Mother's Birthplace: Utah Household Members: Name Age Arthur A Day 26b. 1904 Utah, par b. Utah; Salesman, Furniture Store Aileen Day 21 -wife- b. 1909 Wash, fath b. Wisc, moth b. Iowa Richard Day 11/12 -son- b. 1930 Utah
There are public trees on Ancestry.com that has Arthur married to Elda May Huff, and they had a son, Robert Leon, born in 1944 Ogden, UT, died 1987 Monticello, UT.