my boyfriend is attracted to his cousins

okay guys i need advice on what to do in this situation.. it’s tricky.

i work at a department store and i have been dating someone who works at the same store. before work yesterday morning i was at his house and he was asleep and while i was leaving i grabbed his loo to play music on his speaker (he regularly asks me to do this bc it helps him stay asleep longer).

well yesterday when i opened his phone it was open to porn, but it was like tabs open (it was in an app used to download stuff “securely” idk) and the tabs open varied between porn and pictures of his cousins. one was even a cropped picture of his cousin from a family picture.. i kept looking and he had 3 files in the app one titled “adult” filled with hundreds of porn videos. and one titled “badddd” which is filled with pictures oh his cousins. and the 3rd is called “photos” again filled with his cousins/ random only fan creators.

obviously i’m disgusted by him but there is a bigger issue i need help with. one of the cousins he has multiple pictures of is his younger cousin she is the manager of the department store we work at.. and he lives with her. she owns the house and they have separate homes and he pays her rent.

he has pictures of her younger sister in his albums too. should i tell her? confront him? just leave the situation as is? i am so torn, confused and sick. i’ve never been in this situation b4.

i also took videos if everything i saw bc i was in shock.