Reducing vaccinations reduces herd immunity though.

There’s no polite way to say it. He’s not very intelligent and has a poor grasp of the information that would lead you to see that they’re effective.
If you don’t trust the government or establishment and you don’t have the capacity to evaluate evidence, then anything the government or established medical system says is good must be bad.

The most charitable explanation is that he, admittedly, had a worm eat part of his brain.

You can find reasons that people could be pushing vaccines that don’t do anything, but that doesn’t mean they actually are doing so.