Wonder if he targeted his brother, or if his brother was trying to stop him.
I wondered that too.
I knew a family that had two sons, the oldest of whom was great and everybody loved him, while the younger clearly had problems of some kind and was a social misfit.
No reason...there weren’t even any of the usual reasons for being rejected by his peers - that is, he wasn’t overweight, didn’t have a speech impediment, wasn’t badly dressed and didn’t have any of the mannerisms that “normal” kids attack.
One day in class, he drew a picture of himself shooting up and bombing his school after he had lost a part in a play.
He lucked out because he had a devoted mother. The school called and gave her a chance to do something about it before they reported it to the police. She took him out of school that day and was going to send him to a boarding school that specialized in kids like this, but because she was a stay at home mom with a working husband, she decided to keep him at home.
I was always worried about her because I had a feeling that you never knew when this child was going to change and go off the rails and what might “trigger” that.
But it worked out and he’s now an adult, mildly dysfunctional but employed in a low-end job that he loves and is getting married soon.
I’m sure we’ll know more about this shooter soon, but it does sound as if his brother may have been a target.