Perhaps you've seen a sign outside a church or on someone's bumper that says something like this: "Christians aren't perfect -- they're just forgiven."
It points out an important truth: Although God has forgiven us of all our sins, we still aren't perfect, and we still sin. Even the Apostle Paul -- the greatest Christian who ever lived -- often found himself weighed down by his old sinful nature. He wrote, "For what I do is not the good I want to do; no, the evil I do not want to do -- this I keep on doing" (Romans 7:19). Every Christian can identify with his struggle.
Why do I mention this? The reason is because your uncle doesn't really understand what it means to belong to Jesus Christ. It doesn't mean we're perfect -- because we aren't. But it does mean God has come to live within us by His Spirit, and it does mean we now have a whole new direction in life. We aren't hypocrites -- not if we're following Jesus. But we are honest about our needs, including our need of God. Can he say the same about himself?
Pray for your uncle, that God will convict him of his pride and rebellion. But pray too that you will be a witness to him of Christ's love and peace. He may deny what you believe, but he can't deny the reality of a life that has been changed by Jesus Christ.