- "He was punished for what he did to his brother."
English Language Learners Stack Exchange is a question and answer site for speakers of other languages learning English. It only takes a minute to sign up.Sign up to join this community
He was punished for//what he did to his brother.
The verb punish here takes the preposition for.
"what he did to his brother" is a noun clause used as a direct object of punished for.
He was asked about//what he did for his brother. He denied //what he did to his brother.
I don't think this is anything adverbial per se.