Yes a person does have to want the help, or at least acknowledge a little that they are open to what another has to say to them. If they constantly reject what another says to them directly from God's word, and the proper steps have been taken to show them the proper way. Then this is where the teaching's of the Apostle Paul come into play from 1 Corinthians 5, in which Paul says if they still reject how the word says to walk then they are to be cast out.
Some seem to want to skip the other steps and go straight to casting out the individual and calling them a heretic, and others I have seen confuse accusing and rebuking, and how to do the rebuking. People seem to always come back to Jesus and what he said and acted toward the Pharisees and money changers.
The part they don't understand is that Jesus knew where there heart, and that it was full of greed, deception, and self-righteousness. The Lord knows our heart, but we do not know where one's heart is so we have no business passing judgment on another. All we can do is see by their actions and words if they are behaving as the bible states, and if not then we are to in love help them along the journey in faith.