I mean, the argument is there. But owning a home isn't about pure returns. It's about owning something you take care of, build onto, and give touches of your own. It's a place to build memories with others that can't be so easily taken from you from some landlord. It also depends highly on what exactly he is proposing. To rent the home I have a mortgage on, would be likely 1500-2000k a month (based on the local prices), when my mortgage is half that at a bad rate. I also live alone, which in renting, is just not feasible in most places without it being a significant portion of your income. (i.e. upwards of 1/3 to 1/2 your income in some areas)
Actually, you could literally make the argument that with the money saved by paying a mortgage and not a rent, you can just toss 15% into the market and make even more. This isn't an argument against owning a house lmao, this is an argument that you should invest