Whether it is this incident, or the last few, or the next one. Whether the parents are liberals or conservatives or apolitical, when the youthful perps are mentally ill*, they should not have firearms.
The parents, other family and friends, should be very mindful of these risks. We have enough examples.
We might want to be mature about it also, and not spread rumors the first day that he is a homosexual muslims, because you can tell just by looking.
* He went to a school for mental disabilities and conditions, autism, aspergers, etc.
But even after doing all of that right, it is possible tor a loner with no records, to get 13 guns and ammunition and go on a rampage.