Stress is very stimulating to the brain, especially one that doesn't get stimulated from doing things others do, like a brain with ADHD. Social interaction is so fundamental to us, it doesn't matter if it's positive or negative.
Your kid WANTS to be liked and popular, but because he didn't pick up on the social cues of his peers he struggles and they react to him with more signals he doesn't understand.
example:
A religious friend: "(random topic) is super evil!"
Your kid, making fast internal connections and genuinely (impulsively) asking: "Why, because it's not from God?"
To Neurotypicals, questions have meanings upon meanings. To them, the interaction would indicate he's opposed to the topic because he questioned the topic's authenticity, which means he doesn't like that person because he doesn't like that associated topic.
Which isn't true for ADHD folks, since we tend to take these things at face value.
If you think I'm going on a tangent, I am. But it's all about to make sense.
These interactions are met with awkward stares and passive actions that send a message, but prevent him from addressing them (like excluding someone or not talking with the same enthusiasm). They DON'T tell him where he went wrong. So, he doesn't learn to fix it.
This makes him more assertive, causes him to favor reactions he unequivocally DOES understand even if they are negative. It is way easier for a child with ADHD to just be told how it is rather than being left to read between lines.
He would rather be called names and directly insulted and isolated for actions he knows he caused, rather than deal with the stress of wondering where he went wrong and why his peers are treating him differently than the rest.
I know this because I lived it. It was way less stressful, more meaningful to just be the bad guy. At least then I knew WHY it was all happening, and didn't ask myself where it all spiraled despite efforts to be a friend and landing on "I just wasn't good enough to be with the rest of them."
This is NOT predominantly an impulse issue. This is a lack of social skills and a need for clear cut interaction. Now, he may have missed the cues needed to fit in on his own but here's alist if 5 main things you can try!
Understand his social behavior
Try to get a grip on what's important to him in a positive interaction. Your his mom! This one will be easy 
>It may be strange jokes
>Rambling about experiences
>Asking personal questions (there's not a lot of lines between mother and son, so it might be hard to notice, but he may ask his peers things that are also considered personal)
>physical gestures
>It could be a bunch of things!
Reward the behaviors after allowing him to learn what others value in interactions
Once you have a good understanding, it's important to show him (in a non-confrontational way) what good social behavior looks like.
>make upset, exaggerated faces when he commits a taboo, like interrupts, and calmly/curtly tell him why you're upset without lingering. Make pleasant smiles and gestures when he is minding manners. (what makes this non-confrontational is that it is situational, and not brought up from past mistakes).
>emulate what he does, negative and positive things (not exaggerated, you don't want him to think you are mocking him or even let him catch on at first). If he tries to steer you away from the behavior, ask him why and give him an example of his own behavior, but don't make him think you were punishing his behavior, simply allow him to reflect by asking "why can't I do it too?" "does that feel really fair to me?"
>readily accept any and all apologies or attempts of recourse for small things, move on from them as if they never happened. This might seem counter-productive, but this actually ensures a better learning experience by reducing social stress and not forcing his brain to linger on negatives, missing more possitves. It gives him a better idea of what to avoid.
>thank him for allowing you to speak uninterrupted, for his input, for his attention, and for the happy emotions and value he added to the conversation... But maybe word it differently lol.
>move on from corrections quickly; do not drag them out or go into lengthy explanations. He will learn best if he is provided with many small examples in various contexts and not a big, long one for lots of contexts.
Play pretend (for younger kids)
Let him tell you about his day, each day, with examples of his social life. Maybe you can get into the habit of acting them out! Act out what happened, what COULD have happened, and act out what tomorrow could be like.
Pretned to be him, pretend to be his classmate, the teacher, the counselor, the wizard that was there too, be everybody! Social interaction has a place in our brain that isn't exclusive to reality. A fake interaction is just as valuable as a real one, if not more so because now he can learn in an environment that is willing to "start over" as many times as he needs without consequence.
Stay positive
No really, that's the most important part. The goal is to get him on board with good interaction, not force bad ones like he's doing with his peers.
>do NOT judge him for actions he shared with you. This will prevent him from sharing in these future and curb his social learning further
>take a break of he gets upset
>don't reward tantrums or controlling behaviors
>make quick/clear descriptions of what you want in the situation
>don't say "you did this." Try using "I want you to try this" and respond to "I did!" with "I think I missed it, and I want to see you try it again" and never "no you didn't" because even though you're right, it's best to let him come to the conclusion of wrongdoing on his own.
>apologize too, even if you think you shouldn't apologize. He may be feeling the same things. Set an example and he's sure to follow. Forcing an apology for children of any kind only leads to more sour feelings.
Like with many other things, stay consistent
Allow him the space to share interactions he had throughout the day. Don't get mad at him for them, but ask him questions like "and what did she do after that?" "what did the teacher say?" "was there something you could have said differently?" "was he upset? Why do you think that is?"
Be his mirror with good flattering lighting to bounce off of and DON'T react harshly to his tellings. He deals with enough harsh interaction as it stands, so it won't be productive.
Ask if you can add input by gently saying things like "you know what I would have done?" "can I make a suggestion for the future?"
And don't be upset if he isn't responsive or doesn't want to know. Don't hold him to them by asking if he did the things you suggested or why he hadn't. Ultimately... It is up to him.
Let him come to you, and just share the outcome with him rather then inserting your own emotions.
I hope this helps.
Stressed & Need Advice
My 7 year old is having issue at school with behavior.
Genesight
Advice to parents with ADHD children
Need and advice
