What Causes The Noises In Head?

Hello,my friend 26years old,seems to be hearing noises in his head like rain splashing or many people whispering,it is usually heard in the night,as soon as he closes his eyes to sleep,but it disapears after 2minutes of opening his eyes,he is so disturbed by this noise that it keeps him awake making him sleep during the day,he underwent an auditary testing and it was all normal,he is lately stressed and thinks hes depressed,please help us to identify what is hapening,thank u..e