Well, he actually worked at Wendy's, an one of his rifles had what appears to be an Eotech (under $600.00), the other flip up sights about $100.00.
He had about 1700 rounds according to police, and anybody canllll buy "military grade" ball ammunition, Lake City has been selling it for decades.
As to the vertical forearm grip, you can walk in most gun stores and pick one up, order one, or pick one up off the many tables at a gun show.
I can find nuthin on the year model, of his pickup, or any of his "personal possessions" cost of clothing, video games ect or whether he was acquainted with the buffalo shooter.
I would be interested in your cousins sources, but suspect they are Facebook related, as it would be near impossible to glean such details this early on.
What the shooter did was horrendous, and has caused the rumor mill to run wild. This will no doubt cause questions in those whom are on the fence regarding gun control, and will no doubt fan the flames for more gun control, and government intrusion into our lives.