I've often heard it said that family members are the most difficult ones to witness to about their need for Jesus. They know us too well is often the lament. This may reveal the fact that we're often hypocritical or that our old nature too often is on display. We surely need to give attention to our walk and our talk.
But we are not the only stumbling blocks in drawing others to Jesus. Just as some of us may have been before we came to faith in Him, we tripped over ourselves. We did not (would not) believe. While the door is always open to whosoever will come, we cannot come unless we are drawn by the Holy Spirit. We err when we think we hold the key to the decisive moment of entrance.
As I was reading today, I came to John 7:5, "for not even His brothers were believing in Him." Here is the Christ Himself who lived for 30 years in the same house with His brothers, and He is perfect. He always walked His talk. They knew Him very well as a brother, so there is more to it than the supposition of thinking family "knows us too well."
While our purpose is to glorify God in all we do, only God can draw people to Himself. And so we pray to that end. Jesus' brother James believed only after His resurrection, which is the foundation of the Christian faith. That was the pivotal point for James. That's when He understood fully his own need and the scope of redemption through Jesus.
We don't know what the pivotal point may be for a family member. But it is surely that they must understand their need and see Jesus as their redemption. We, ourselves, must walk in a manner worthy of our own calling in the meantime. And lest we think it's about us, know that it's about being an ambassador for Him.
Therefore, we are ambassadors for Christ, as though God were making an appeal through us; we beg you on behalf of Christ, be reconciled to God.
~ 2 Corinthians 5:20
Image ~ A Close Game
Harry Brooker, 1848-1940
public domain 
