I am looking for Mr. Major Alexander and family born abt. 1840 ln Ms. He is on the 1880 census living as a servant in the home of Roburta Willroy/willoy .

Greetings and Welcome
Took a look at your query and found Major Alexander on the 1880 as stated.
A closer look indicates Willroy is the sister in law to the head of household. Could there be an enumerator error in determining who is living in what household on this page? Would a City Directory be of assistance? Or other record sets?

The Census Page 1880