At the time, he implicitly suggested that one reason he doesn't like attending church nowadays is that the worship services have changed from what he was used to. His question: God doesn't change, so why should we change the way we worship?
I don't think he knows, but that alone is a very clear argument for Islam. What bothers him, I think is that more "contemporary" services cater to a younger crowd, trying to bring them into church rather than push them away. So they use contemporary music, live bands in the worship service, instead of singing the same old tired hymns with an organ and a choir. But that's what he finds comfortable--the hymns and the choir.
But did people sing these hymns with a choir and an organ while Jesus was alive? Surely not. What about in the first millennium of Christianity? Nope! In fact, singing hymns is a fairly recent development that at best only goes back a few hundred years. That means that yes, sure enough, worship has changed. It changed language (from Aramaic, to Greek, to Latin, before ever making it into English, and it's taken many other courses as well) as has even the very "Word of God" according to Christians. It's changed in many ways over the years and will continue to change. Do you know why?
Because Christians aren't worshiping the way God told humans to worship Him. What makes a person think that God likes hymns any more than he likes rock? The proponents of contemporary worship would certainly consider that any grateful noise they make should suffice if it makes them happy and elevates their spirits. And isn't that what it's all about? Maybe, if you're Christian.
That's why it works as an argument for Islam. You see, Muslims have been worshiping the exact same way since the time of the last Prophet of Islam (Muhammad ﷺ) and that's over 1400 years! They pray the same way, they read the same book in the same language, and conduct worship services exactly the same way. Do you know why?
Because they were taught, by God, how to worship Him, and that's what they do.