Glad your friend will heal from his attack.
I will add this, having spent the better part of ten years behind or managing a bar. They can be extremely unpredictable because not only do you have strangers mingling, you have strangers consuming alcohol, sometimes at an alarming rate.
I've had people try and blindside me, stab me and generally try and f**k me up in bars! None suceeded but, I will not enter into another probably for the rest of my life. I don't drink anymore, granted but, even bystanders uninvolved in the fracus tend to get injured. Testosterone and alcohol have always been a dangerous mix, add stupidity and it can become deadly.