Check his bank account

Ugh

those drivers should wear helmets and a vest then.

Tell him to get on a bike and then ask him how much of a hazard to drivers he feels like

The opponents say that every time. "No one ever uses them."

I can't speak to those specifically, but I see bike lanes in use all the time. Every time I'm in DC, cyclists in the bike lane, no matter the weather. Every time I ride a path that used to be a railroad, there are dozens of people also using it.

I'm in an abandoned rails group on Facebook, and some of them are very angry about abandoned railroad lines being converted to bike paths. The line will have been abandoned for decades and they still whine. "They should run trains on that!" To abandon a rail line, the company has to demonstrate that there's not enough business in the line to make it viable. They can't just toss it on a whim. Occasionally I've asked how much money they personally will contribute to reactivating the line, to which they inevitably say - apparently in earnest - the government should pay for it. Did I mention these guys are almost always right wingers?

It's so bad, that I created this gif to use:

What few "bike lanes" we have where I live still get regular use.