Just another responsible citizen exercising his rights

This "relative" is a bigger threat to your gun ownership rights than anybody calling for an outright ban on guns. 

Horsley described the boy's parents as shocked by the incident and cooperating with investigators, who found the gun belonged to a relative who has been living temporarily with the boy's family.

An outright ban will never happen, unless the credibility of the "responsible gun owner" argument is lost and this idiot helped to do that very thing.