Just like with other things, there need to be BOUNDARIES and limitations. Set LIMITS and stick to them. If he is BORED..give him things to occupy his mind & body to help around the house. He's not a guest at a hotel.
I'm assuming (knowing how my youngest brother had everything handed to him and being the youngest got by with all kinds of stuff I didn't as the oldest)that he has gotten by with far too much for far too long. You may have to gradually tighten up the reins, but if you don't, he'll think he can go to work and talk all day and play games on the computer and there are no consequences.
MAKE & STICK TO CONSEQUENCES for talking on the phone outside those guidelines and boundaries. Otherwise, what's the point? Don't make it chores...but rather helping a neighbor, grandma, a church, etc. LESS PHONE TIME THE FOLLOWING WEEK, etc. Things that will make him think but on the other hand....maybe something that will help him develop into a GOOD UPSTANDING HELPFUL CITIZEN.
Life is about BALANCE and being able to balance that. The older you get the MORE you need those skills. What other hobbies does he have? If he doesn't have one.......do one or find one.....experiement and experience with DAD or another sibling or neighbor or cousin. CREATE family time. Take an archery class, painting class or something that they can "do something they've never done" and get some experience.