My BS16 has friends like that. So rather than say that he could not be friends with them, I decided that my home was where they should be (to keep an eye on them). I have snacks and juices for them, even a meal if they are here when we eat. Always nicer to be close to them then far away.
I get to see the parents of these boys all the time, they thank me for the things I do for there boys, some question how I have 10 teen boys in my house at one time. All I say is the rules are written out and they are for all kiddo to enter my house. If other people children do not follow the rules, I banish them in front of their friends and according to my son, while they are banished no one talks to them until the banishment is done.
Some parents find it hard to discipline, create rules, or just be a parent. Teens need guidance. Encourage them to come to your home, set the rules upfront and stick with them. When they leave let them know that your son is to be home at XXtime so that they can meet their curfew. If it does not happen the next time say no and let the other teen know you are disappointed in him as well.

I am with you! I am so tired and drained my son is 15 and well is really pushing me and his father to doing something we dont want to do. He is smoking behind our backs and drinking. Yesterday he left and did not ask permission and still has not came back. I am so tired. And at my end with him.

He acts out awfully and beats up little brothers can be disrespectful to me. He is a out of control teen.

I have tried to have him and friends here and be kind to all. I talk to all the kids as if they where my own.

I just dont know what to do right now. I feel beat down.

kids not coming home is big thing and to tell you the truth my BS17 tried that. He did not like the consequences either. I called the cops and had him picked up, they reemed him a new a$$ and he has not pulled it since.
My advice would be to you to call the cops and have BS15 charged. In this day and age, some parents, including me, need help at times and the best help is the police. If your Bd is allowed to continue with this into adult the consequences will not be good. Get a handle on this ASAP.
Write Rules and Consequences out, if BS doesn't follow them and they are severe, call the cops. BS maybe referred to CPS, however, this is a way to get help in controlling his bad behavior. Once kids are in the system and the system is consistent (not all are), the kids get the picture.
If you take my advice, let me know how things turn out.

I CALLED THE COP'S ONE TIME MY SON STAYED OUT
I TOLD THEM HE DID NOT CALL OR CHECK IN,THEY TOLD ME TO KEEP CALLLING HIS FREINDS, I WAS PISST AT THEM IN THERE LACK OF CAREING,NOW I;M GOING CRAZY AND THINKING ALL KINDS OF THINGS
HE FINALLY CALLS,COMES HOME LIKE IT WAS NOTHING
WITH HIS SMART MOUTH, THATS GOTTEN WORSER, NO
CURSEING JUST TALKING LOUD AND TALKING JUNK,
LIKE I;M SUPPOSED TO PUT UP WITH IT .THEY ARE TAUGHT IF WE TOUCH THEM WE, WE WILL FACE CHARGES,,,,SO I DONT TOUCH HIM,SAD TO SAY BUT THESE DAYS EVEN WITH A FATHER OR STEPFATHER
THEY STILL ARE DIRESPECTFULL,AND THEN HE HAS THE NERVE TO ASK ME FOR MONEY, ORSOMETHING HE WONTS I TELL HIM NO, YOU MUST REALLY THING I'M A JOKE WHEN I SEE CHANGE YOU WILL GET SOME CHANGE......