My sons fighting has become violent

I’m a mother of four, two daughters who are 19 and 9 and two sons who are both 11. Let’s call my sons John and Sam. John and Sam are twins. John has always picked on Sam from teasing to punching. My husband and I never thought too much of it as we all know brothers fight, but Sam used to never fight back. One morning Sam kicks John in the kitchen and my husband chose not to say or do anything being happy Sam finally stood up for himself. When my husband told me I thought it would end the bullying from John. I was wrong. Instead the insults got harsher and the punches got harder. This continued for about 3 months, My husband and I had been trying to deal with it as it was becoming violent. During dinner one day after bickering and insults being traded between them, Sam got up, picked up a lamp and went for his brother’s head. Fortunately he missed, but that started a brawl between them. I swear it looked like they were trying to seriously hurt one another. It happened fairly quickly, my husband got Sam up stairs while John just yelled “I’m sorry!” to Sam. John had to get stitches and we have been keeping them separated, my oldest daughter now sleeps in the basement (she wanted to for more privacy) giving John her room and Sam now sleeps by himself in his room. My youngest daughter is now terrified of Sam and everyone is on edge. I want to try therapy or counselling but my husband thinks that would be blowing things out of proportion. Any advice? Or am I overreacting? via /r/Parenting https://ift.tt/2OEjf1C