This is a complex situation. At 15, the story of angry behavior can be rather... old. I am a sort of expert in "behavior Modification", but not a professional. I mean I had studied the subject about 15 years ago. I have studied carefully about 8 or 10 books on "Behavior Modification".
So, for what you were telling, this behavior of your brother has been conditioned outside home. For you do not tell us of any incidence of fighting at home but the last one or so.
Well, someone can be conditioned to be bad tempered outside his home, and you cannot do anything about this condition. I mean, the agents that are affecting the behavior of your brother
are not under your control.
Perhaps, his angry mood is related to debts he have to pay. For the drugs, even mild drugs, like marijuana, are not any cheap. It is no they are not cheap, but they should be consumed almost daily. So, when he is with withdrawal symptoms, he would feel angry, moody, or prone to show a bad attitude.
But in general, the best approach to a bad or moody attitude is to ignore the behavior.
This is contrariwise to the general attitude of most people.
In general, people wait till his child or his brother is having a bad attitude to have a chat with him, and tell him this or that speech.
The idea of Behavior modification is that "words have an effect similar to conditioned reinforcers". That is, words do reinforce the frequency of behavior we want to downplay.
So, the best approach is the contrary. You have to ignore the first signs of bad behavior, as if you were not aware of it. Only when the behavior is outright aggressive or dangerous, you have to actuate to stop it.
Then, if the advice is not to take notice of moody behavior. But you should have to act often, with words and signs of friendship, when the person looks like normal, or shows an indifferent mood.
The general idea of Behavior Modification is that reinforcers should increase the frequency of the good behavior, or at least the frequency of the indifferent mood, to make it occur more and more frequently.
The reinforcers should be not only words, or a friendly chat. You should also use other more powerful reinforcers, like sweets, beer, or any thing you know he likes. You should invite him to a bar to have a beer, or to movies, or should you rent a video disc that your suppose he would like, and all this.
These reinforcers should be used, when the behavior is normal, or at least indifferent. But not when your brother looks angry or depressed.
Most of the symptoms of depression and the blue mood are usually reinforced at home, by people who think that the sad or moody person needs help. Of course he needs help. But this is no the best way to help him.
This I am saying is totally contrary to what people is doing in these situations.
So, you probably do not understand or you do not agree with what I am saying. If you do not agree with me, I beg your forgiveness. And this is the end of my post.
If you do not understand well what I am saying, you can asked me what part you did not understand.
Yours truly,
John Galaor