Or did he die because his heart was damaged or weakened by a vax shot ?
My guess is he died because he went into the Rio Grande without wearing a life vest/flotation device. If that is the case, then his entire chain of command should be relieved of their duties immediately. These "leaders" demonstrated their unfitness for command.
This is merely my perspective as a former Army officer, 8+ years active duty, Air Defense Artillery, platoon leader and battery commander.
There should have been strict rules of engagement to our soldiers from their unit commanders. My soldiers knew when I was "serious as a heart attack", and they paid attention to what I was telling them.
Being on the border, that would qualify as a "serious as a heart attack" moment.