That's easy: whichever solution you pick, you are sure to find biblical support for it.
Do you want to ignore everybody who challenges your faith? Apostle Paul left when he discovered opposition to his preaching:
Do you want to interpret his statement as challenges? Apostle Paul did NOT leave when encountering opposition, but instigated ceaseless debate with those most likely to disagree with his gospel:
Do you wish to wash you hands of him and move on? That is exactly what Jesus and Paul said to do in case you meet with those who refuse to convert:
If I were a Christian, I'd argue as follows: God is not only capable of stirring up a person's spirit to motivate them to do what he wants, but He actually does this:
Paul agreed with certain pagan poets that it is within God, that we live, and move, and have our being:
Therefore, since our motives are constantly stemming from God, and God is able to stir us up to do something specific, unless God motivates you to defend the faith or evangelize a particular person, your choice to live and let live is God's issue, not yours. If God wants you to take a particular stance toward your uncle, according to your own beliefs, God will surely make this known to you.
