I searched the 1900 Census for an Arthur Cooper, son of
Ben or Benjamin, living in VA, born ca. 1897. I wasn't able to find
anyone fitting that description. There are three Arthur Coopers born
ca. 1896; none of them had a father named Benjamin.

I then searched the WWI Draft Cards. Again, no one born in 1897 There was an Arthur in Norfolk, but he was born in 1894.

There is only one African American Ben/Benjamin Cooper in VA in 1900 born between 1850 & 1860. He was living in Henrico County, with his wife Ann, and three grandchildren.

I wasn't able to find your grandfather in the Social Security Death Index, either.

What was your grandmother's name? I would be happy to search the census records, again, if you would like that information.

If I can find him with your grandmother in 1920 or 1930, I might be able to trace his family backwards.