Ah I understand, let me be more specific, and answer some questions.
When it comes to farming, we don't put farmland in cities, in rural areas cars do make sense.
Energy generation doesn't have to be done in cities either.
As for sewage, yeah it takes up space in cities because you can't tranport it out, but it's small compared to the entire city.
The parts that are unsustainable are the vast swaths of single family homes.
The maintenance costs for these areas, in the form of electcity, water, sewage, roads, are higher than the tax revenues generated by property taxes.
It takes a long time for this tax deficit to show, about 30ish years, and it can be delayed by builidng and developing new suburbs. The taxes from the sales and other newness generate some new income. The federal government will also subsidizie a lot a building a new road, but notably not maintaing them. Which after 30 years can be more than the road would cost to build new!
But after a while the maintenance comes due, roads fill with potholes and need replacing, sewer and water pipes start leaking due to wear, or even the ground moving. Electricity lines blow over, knocked by trees, or hit by drivers need to be fixed.
The cost of roads and car dependency is not cheap. A study came out that it costs Americans an average of $20k a year for car dependency. About half that is owning a car, and the other half is taxes spent on road infrastructure.
In just slightly denser areas, where the government hadn't regulated things like setbacks, minimum parking requirements, and soley single family housing, there is enough revenue.
So what ends up happening is these denser areas subsidizie car dependent suburbs.
And all the while suburbs with car only transportation have tons of traffic, because when you get down to it, a single lane of cars just can't move that many people.
Now there are some exceptions to this. I live in an area with astonishingpy high property values, nearing 1 million for a normal house. This generates a lot of revenue, but it creates an housing affordability problem. This problem would be alleviated if there was increased density if the local government didn't zone 84% of the land into single family housing only.
And it would still increase tax revenues in my area.
A good bet is alternative media, things like kurzgesagt, verisitium or other science outreach programs.
The other thing is education, engage with his education, and teach him yourself to think critically.
And I hate to say it to say it, but religion conditions kids to brainwashing. Even if not extremists.
Feel comfortable pointing out flaws in Christianity and question them with him.
And lastly, try not to be argumentitive. You need to carefully tease him out of these beliefs, not destroy them.
That would feel like you are attacking him and will probably be counterproductive.