Hi: everyone

I need help locating my Great grandmother Sarah Elizabeth Manuel's father
Greenberry Manuel He was born in 1812 in Tennessee
someone said he was full blooded Cherokee Indian and
it was stated on his Civil War records. I can't find
Greenberry Manuel in the Civil War. I don't know if
he was in Tennessee or Arkansas.
In 1860 he was in Searcy Co. Arkansas acording to
the 1860 Census.
any help finding Greenberry Manuel Civil War records
will be a great help
thank you.