“sometimes when I’m down here… i listen to the water… and it sounds like people talking…”

He probably has MES, Musical Ear Syndrome. I got it, it’s really not as scary or weird as it sounds. Basically our brains mistakenly interpret some white noises (running water is a big one) as faint music or voices. But it’s not really a hallucination, because at the same time our brain is aware it isn’t real and it’s just coming from said noise. It can actually be quite pleasant, beaches often sound like a quiet symphony. Only occasionally will I hear voices and mistake it for my girlfriend or something before realizing it.