"Federal law generally prohibits possession of firearms and ammunition by people who have been found by a court, board, commission, or other lawful authority to be a danger to themselves or others, or to “lack[] the mental capacity to contract or manage [their] own affairs,” as a result of their mental condition or illness."
Research Texas state laws on mental health reporting, including what is regulated and what's not. Find related gun law details from Giffords Law Center to Prevent Gun Violence today.
giffords.org
The shooter did have mantel problems. So his mother said.
But his family never got him help or reported it. Even after he was caught with 2 cats he had killed in a bag.
If they did report him. He would never been able to buy a gun.
Mind you his family have been in trouble with the cops.