Alex Jones has been sued for defamation; see Alex Jones Retracts Chobani Claims to Resolve Lawsuit - The New York Times
The basis of the lawsuit were the reports published on Infowars (the website and YouTube) that said
the (Chobani) factory in Idaho, which employs refugees, was connected
to the 2016 sexual assault of a child and a rise in tuberculosis
cases. The reports were promoted on Twitter under the headline “Idaho
Yogurt Maker Caught Importing Migrant Rapists” and were spread widely
online.
The suit was settled and Alex Jones retracted the stories because those "facts" about Chobani and its owner, Hamdi Ulukaya (Wikipedia) that were published by Jones - sexual assault of a child and a rise in tuberculosis cases - were provably false. There were no proven cases regarding sexual assault, or documented rises in tuberculosis cases in Idaho or caused by the yogurt. Such libel impacted Chobani's business and Ulukaya's reputation, so he sued Jones.
Evidently the lawsuit was settled before going to trial, because Jones broadcast that
“The tweets and video have now been retracted and will not be
reposted. On behalf of InfoWars, I regret that we mischaracterized
Chobani, its employees and the people of Twin Falls, Idaho, the way we
did.”
Those false reports were published - on a website, on Youtube and Twitter - and that satisfied the requirements of libel, which is the publication of provably false facts. Libel is a written or published defamatory statement, while slander is defamation that is spoken by the defendant. (Public figures have a higher threshold of proving libel; they must prove actual malice. Ulukaya may or may not be considered a public figure.) For a full outline of defamation, see Defamation, Slander and Libel | Nolo.com
Unless Jones has retracted the provably false facts he has (allegedly) published about Sandy Hooks and 9/11, or somehow noted that they were his ideas or theories and not provable facts, or that he was simply retelling the facts he had been given, he could be sued. The lawsuit above cited Jones'
previous contentions that the Sept. 11 attacks were orchestrated
by the United States government and that the 2012 shooting at Sandy
Hook Elementary School in Newtown, Conn., was a hoax concocted by
those hostile to the Second Amendment.
so he does have a record of commenting or reporting on those incidents.
Jones has also Apologized for Promoting ‘Pizzagate’ Hoax (The New York Times), possibly because he was threatened with a lawsuit. And so he does appear to have a Modus operandi (Wikipedia) for this style of reporting and retracting stories.
Jones or anyone else could be sued if they published what he called facts about the Las Vegas victims that were provably false. That would depend on the facts of the case: the victim(s) and the people or news sources that allegedly libeled the victim(s) by publishing the "facts."