The Bible does warn us against thinking that we can go through life thumbing our noses at God and expect to get by with it. Sin always has consequences - and its consequences are always bad. The Bible says, "You may be sure that your sin will find you out" (Numbers 32:23).
Does this mean that everyone who defies God and chooses to leave Him out of their lives will end up like your friend? No, not necessarily; some people apparently glide through life without ever encountering any serious problems, in spite of their unbelief. But even then, down inside (I've found) their lives are empty and meaningless - and after they die, they can expect only God's judgment.
But God doesn't want us to live this way - and the reason is because He loves us. He knows (far better than we do) that a life of sin leads eventually to sorrow and regret and pain. But He has something better for us: a life of joy and purpose and peace, which comes as we turn to Christ and learn to walk with Him.
Pray for your friend, that he'll realize the futility of his ways and open his heart and life to Jesus Christ. The Bible's promise is true: "You will fill me with joy in your presence, with eternal pleasures at your right hand" (Psalm 16:11). And if you've never given your own life to Christ, do so today.