Sister's boyfriend is over all the time?!?

My sister (age 15) has a new boyfriend (almost 18) that she's been dating for about a month, though they've been friends for about a year.

The kid is annoying me!

Well, since they've started dating, the kid is over here everyday! He brings her home from school (around 2:30), and he stays after about 9:15pm or so.

I come home from school (college) and the boy has parked and consumed my/my family's entire driveway, so I'm left parking on the street and walking to my house in the rain.

He gets in the fridge and gets Gatorade's, so I bet one day I'll be left with none to take the school because he's drank them all.

He comes over on the weekends before I'm even showered and out of my pajamas, so it's kind of awkward.

He stays so late most nights that my mom is having to feed him dinner, so we don't even have family dinners anymore. And if we don't feed him, it's just awkward because we're eating and he's not.

When he gets here after school, he goes to my sister's room and naps until 6:30 while my sister does homework in the living room, so I have to tip-toe around my house and whisper so the kid can sleep.

When we are all together somewhere (at the table, in the car), he talks 100% of the time, and he's so loud! Nobody can hardly get a word in, and I can only be near him for a few minutes because it's so loud and constant noise!

Is it wrong for my to be annoyed and angry about this? I am being selfish? I feel like I can't even live comfortably in my house because he's here all the time. He has a great home life with everything a boy his age could want (his parents are extremely rich and active in his life), so it's like he has a bad home life and "get's away" by coming over here.

I tried mentioning to my mom nicely that I had to walk in the rain to the house because the guest parked in the middle of the driveway and took up all the space. She just shushed me and said it was okay. My sister likes him too much to ask him to back up a bit, and doesn't see a problem with him being here all the time. And my dad thinks, "I'd rather them be here, than anywhere else."

Should I just shut up and get over it? Or should I politely ask the boyfriend to ask before he takes Gatorades, makes sure the homeowners are home before parking in the driveway and taking their spot, and to take his naps at home, etc? He only lives a few minutes away, so he can just zip home and get food, zip over after his nap, or ride his bike to our house. I understand I should be nice and polite to guests, but I feel like he's practically moved into the house! Anything I can do?