How do we talk about the Faith to people who talk about never being able to "feel" God?

A friend of mine who has drifted away from the Faith said that, every time he prayed, he never felt like anyone was listening on the other end.

A somewhat dismissive–though possibly true–response is that sin can easily get in the way of our ability to experience God in our lives. If you're entangled with some habitual sin, then yeah, it's going to be hard to receive grace in prayer and the sacraments.

I don't think that response does sufficient justice to this experience, though. St. John of the Cross writes about the "dark night of the soul" where God allows a person progressing far in holiness to feel completely cut off from Him. St. Therese of Lisieux and St. Theresa of Calcutta both experienced periods in their life of feeling cut off from God in prayer, even though they are some of the greatest saints of the modern age.

Closer to home, I'd say I have some subjective experience of God's grace in prayer at times, but I wouldn't say it's very emotional the way some people talk about it. My wife, for her part, has been a consistently practicing Catholic all her life and hasn't really felt anything in the way of subjective emotional experience in prayer. Is there something about modernity that makes it harder to "feel" God? Is it something to do with different individuals' temperaments and how they relate to God? How do we talk about the faith with people who want a relationship with God, but never have any subjective experience of that relationship? Is there any approach beyond just making an act of the will towards faith?