He corroborated the statement of his brother.

confirmed : (of a person) firmly established in a particular habit, belief, or way of life and unlikely to change their ways.
disproved : prove that (something) is false.
condemned : sentenced to a particular punishment, especially death.
seconded : formally support or endorse (a nomination or resolution or its proposer) as a necessary preliminary to adoption or further discussion.
corroborated : confirm or give support to (a statement, theory, or finding).


Synonym of corroborated is confirmed