Please I need help on what to do?

I'm seriously getting tired of my older brother. I'm a 17 year old girl and he's about Yo be 20. Well anyways. I think he's really stupid. He says he's going to be a medical istant. Yet he drinks and smokes. He goes to heald college. He freaken missed his midterm. And I feel so bad for my parents for paying all that money just to get him into the college in which he's not even trying hard for. He missed his midterm I bet for doing something stupid. I feel horrible for my mom. She has diabetes. And anything that gets her mad can immediately cause her to go to the hospital. My brother doesn't even have a job nor tries hard to find one. He's always asking my mom for money to go "eat" yeah right he goes smoke with his friends. And I just feel So bad for my mom. I dont want anything to happen to her. Plus his actions are really causing me to do bad in school. He comes home late and he sleeps in my room. He gets home like at 5 in the morning from being with his friends. And he wakes me up and I can't sleep anymore. I think he really needs help. I think he's stupid and dumb for not graduating and ditching school in high school. Oh and he didn't receive his diploma because his dumb *** didn't cross the stage and they gave him a chance to get his diploma by attending summer school. And he didn't do it. He's really causing Alot of problems. What do you think we should do to help him stop. Btw he's my half brother. And we dont really get along so that is why I am asking this. like should he go to a special place to help him?