Hvorfor er det ikke "endeligt"?
Is it possible to start with the adverb, as in:
"endelig stoppede hans bror ham "?
Yes, and good job on the word order!
My answer was not accepted... How do I report it?
I don't know if your version should be accepted as that would rather be a translation of "Finally, his brother stopped him."
And I have no idea how to report sentences.