I think the reason some people might believe this claim is because we’re taught in school that the moon’s gravity causes the tides. I think the reasoning goes, “well if the moon’s gravity can affect the tides, surely it can affect smaller things too”
Well, now you made me find this paper: https://www.science.org/doi/10.1126/sciadv.abe1358?intcmp=trendmd-adv
OP’s friend might have read something based on it too. This is really weird. I guess more reading is necessary to know if this paper was already debunked or not