Ok I am a 16 year old teenager and I cannot help but to read your question. I am also an older brother and I don't get along with my sister. But its pretty normal for sibling to fight and say those things. It gets better with time.
I have read your question about your son not setting his priorities straight. I have a suggestion. I know I'm young but I used to be this way, but my father has set me straight.
I have heard all about "the speech" and how all the things I do in school is not for my parents benefit, but for my own benefit. You can always try a strict private school but otherwise here are 3 suggestions.
First, Martial Arts, I suggest a school that is a family owned business, with teachers who have had over 20 years of experience in Martial Arts. I suggest Tae Kwon Do, or Hapkido. Stay away from franchise schools like ATA Karate and National Karate. They are only after your money. My father used this on me. Make sure the teachers are older. The older they are the hardened and strict they are.
Second, I suggest bootcamp. There are bootcamps run by the Marine Corps and ex-military. These guys will set you straight and really fast. But this option is usually for juvenile delinquents. So your son may not be a good candidate for an option like this one.
Third, is Dirt Therapy, here are a couple links
A Korean Pastor had a son who was not happy with his life. He watched tv all day and did nothing. He was very rude and selfish and screwed around. His father grew tired of it and tried everything! He yelled at him, took away his son's car, his phone, his computer and his tv. But nothing helped. So he asked his friend, who was a farmer and a pastor. His friend told him to have his son work on the farm. So he took his son and left him in the farm for long time. At first his son hated it, he swore and threw a fit. But one day, he just started working in the field. A few days later while he was working in the field, he just broke down in tears. He had realized how much pain he has put his family through and from then on he prioritized everything. He finally heard what his father has been trying to tell him the whole time, through dirt.
Try a farm that is run by a friend of yours who is willing to take your son in for a few months. Have them set rules and boundaries. Have them be strict with your son as well.
I hope this will give you an idea. Good Luck.