I've seen a number of churches struggle with this. Take music for example. Some churches are debating to what extent they should change their music. Obviously, the answer is not the same for every church. It doesn't work that way.
Every church needs to work through how to be relevant to the people they have the ability to reach.
He needs to think about the issues that young adults face, the issue of character, the issue of purity. The post-modern generation believes that truth is whatever you decide it's going to be. As a teacher of the gospel we have a responsibility to introduce God's truth as absolute truth. Know what they read, know what they listen to, what they watch and how they think. Relevance means that you answer the issues facing young adults with the Word of God.