i'm completely disgusted by my brother and i don't know how to pretend i'm not

gonna start this off by saying that i know that teenagers are gross, it's a rough time, sometimes their hygiene isn't ideal. But think of the crustiest kid from back when you were in school, and times that by 100 and that's my brother He's 16, about to turn 17 in January In the 2 weeks i've been staying with him he hasn't showered once. His only two interests are sports, and video games (specifically fortnite) He'll 'play' sports for a few hours everyday (play is a very strong word, he just hits a ball tied to a tree) comes in sweaty as fuck, eats his body weight in food, and then goes and plays fortnite the rest of the day. but it gets worse 2 days ago i decided i'd tidy his room for him, since it was getting too bad to ignore. the mess was spilling into the hallway and the stench coming from his room was starting to make the whole house smell bad. i did his laundry, came out with 2 bin bags full of half moldy food, and just when i was finishing up, i decided to look at the mini bin under his desk because there was still a pretty bad smell in the room. it was FULL of piss. i went and told my mom straight away. turns out this kid wouldn't even be bothered to get up to pee while he was gaming. he just peed into the bin and left it there, next to his hot PC it was rancid. my mom told me not to tell him that i knew about it, but bro i can't even make eye contact with him i'm so disgusted what the fuck do i do Edit: my parents are amazing people, and i don't think this is their fault at all. they raised me and my older brother to be great, functioning adults. my younger brother was hygienic up until the point my parents decided it was going to be up to him to shower and stay clean. They still try, they force him to shower, gift him hygiene sets to encourage it, but it never sticks. And at almost 17, i don't think it's their responsibility anymore. they give him access to hot showers, and soaps, they cant constantly force him, he's not 5