I think what Trump was trying to say (which is a miracle if he says anything close to being coherent, and a complete sentence) is that "warhawks" never are in combat, and if they were that they would have a different attitude about war. Of course he's a guy who faked a disability to avoid being drafted for military service, which is what is normally called a coward. An entitled coward, to be fair.
So I don't think Trump's comment was technically a threat, but it is consistent with his usual violent rhetoric. For a guy who is supposedly anti-war he isn't anti-violence. Remember, he sat and watched the Jan 6 rioted enfold and expand for nearly three hours before he sent a message for them to stop. It's as if he was waiting to see if the mob succeded before he told them to surrender.
So it depnds if the law includes a hypothetical of certain death as meaning a threat. Trump's comment was sloppy and poorly framed, but what else can we expect from an old man suffering from early dementia?