Options for dealing with ranting/demented neighbor?

Recently, a neighbor, who lives in a town house next to the condo I live in, has starting losing his marbles.

My Japanese skills are almost nonexistent, so I don’t know what he’s saying. But basically, around late morning, he comes out of his house and starts yelling at the top of his lungs. Whatever he’s saying, it sounds really angry. The target of the anger isn’t clear, but one time he appeared to be yelling at a neighboring house (like the house itself). He usually comes back out for another round in the early afternoon.

He seems very old, well past 70. And he appears to live on his own. So I’m guessing it might be dementia setting in?

So I’m wondering, what options are available with this in Japan? Is there some authority I should report him too? Or is there some legal procedure I could initiate? It’s quite bothersome. Like, he is yelling as loud as he is able, and it echos across the neighborhood. It’s been going on roughly 2 months and I doubt he’s going to stop it until something forces him to.