I don’t think you could categorise is as ‘false’ given that link you’ve provided. More unconfirmed rumour at this stage.
Johnson’s claim that Caine blocked a nuclear order has no corroborating document, on-the-record source, or court filing. What is confirmed is that Caine has consistently urged caution, that Trump has repeatedly contradicted his own advisers, and that the gap between the commander-in-chief’s rhetoric and the Joint Chiefs’ public posture is wide enough to give viral rumours room to breathe.
Until the Pentagon responds, the story remains a claim, not a fact.
I don’t think you could categorise is as ‘false’ given that link you’ve provided. More unconfirmed rumour at this stage.