Unfortunately no matter which type of mental health disorder your son has, he requires intense therapy as his behavior is definitely problematic and will only worsen. Changing your parenting structure will most likely not be enough for him, so I would urge you to reconsider therapy. If your son had a heart issue you would not question taking him to a cardiologist, well this is a behavioral issue and I would strongly urge you to take him to see a mental health professional for treatment.
Now if you truly want to go about this alone than what you can try to do with him is a form of narrative therapy and role-playing. Here you will read to him stories and books with moral ending and messages and then you want to relay these moral messages to him and his daily life so that it applies to him. In addition, try to role-play where you and him play the aggressor and the victim so that he can learn empathy more and start to realize the impact of his behavior. Here are a few narrative therapy books I often use as examples:
"Stand in My Shoes: Kids Learning About Empathy" by Somson
"What If Everybody Did That?" by Javernick
"My Mouth Is a Volcano! " by Cook
"I Just Don't Like the Sound of No! My Story About Accepting No for an Answer and Disagreeing the Right Way!" by Cook
"I Just Want to Do It My Way!: My Story About Staying on Task and Asking for Help " by Cook
"Cool Down and Work Through Anger" by Meiners