Guess he doesn’t have parentS. Mother died a year ago. Something “off” about his father. Seems that he was/is basically raising himself.
Another article on FR says he was adopted at birth. The adoptive father died awhile ago (ten years ago?) and the adoptive mother died 3.5 months ago at the age of 68. He has a younger brother that was also adopted by the family (I’m guessing a step-brother).
He had lived with relatives after the death of his mom, and had recently moved back to this school area to live with a family that knew him. The family allowed him to bring his guns - but to keep it in a gun safe - although the kid did have the key.
Seems like there were lots of warning signs. That is one thing about schools that should change I think. Instead of just treating threats or bullying or theft “in-house”, they need to get the police involved imho.