My bro put the earphone while the phone charging but he say it isn't dangerous cz he play 1 app only that doesn't let the phone heatup. is he right?

Cell phones: Cell phone radiation is low-frequency & low energy. It is actually nonionizing radiation. Unlike high frequency wave ionizing radiation, it is doubtful it can cause cancer in humans. Cell phone radiation was however, shown to ^ risk for developing schwannomas in rats & gliomas in other animal studies. REF: https://www.mskcc.org/blog/do-cell-phones-cause