The age to purchase a shotgun or rifle in Texas is 18. Anyone younger than 21 can't buy a handgun.
Under Texas law, anyone who allows a minor to gain "access to a readily dischargeable firearm" can be charged with criminal negligence. Law-enforcement officials likely are exploring that option in Friday's Santa Fe High School shooting because suspected shooter Dimitrios Pagourtzis got the two firearms he used from his father, according to Gov. Greg Abbott.
https://www.usatoday.com/story/news/...aws/625372002/
Sounds like Dad will be in some trouble