My buddy is about to become a first time dad

I really hope it works out for him and becomes the greatest joy in his life. But I can't shake the feeling that it might end up being a complete distater, because that man, bless his heart, has no idea what he is getting into. He actually thinks that his life is not going to change in any significant way and things will "just work out".

Let me set the stage for you:
My buddy is in his mid forties and had never wanted kids before. He's the type of guy who goes out every weekend (and some weekdays) with his wife to meet their friends, hang out and get drunk. They have friends over basically every single day, enjoy life and regularly go on mini-holidays during which they barsurf their way through the neighboring countries. And he thinks his life will not significantly change.

He's also in a band, they practice at least twice a week and are currently planning their next album. Needless to say, that also involves lots of partying and waking up somewhere around noon. He also has another time-consuming hobby that requires him to go off-grid for several hours at a time. Again, he thinks his life will not significantly change.

They spend ungodly amounts of money in grand home renovation projects and have a spotless house that looks like the cover from one of those magazines. And let me reiterate, he thinks his life will not change much.

He is firmly convinced that having a kid will only be a mild inconvenience to their lifestyle, as they are surrounded by extended family.

I have tried injecting some realism into his worldview, but he is adamant that it will be different for them, and will somehow be able to just go on.