Gerry will know the vital signs of heart problems without machines
Kate will know the vital signs of serious drugging without machines
I know a bit about cardiology having spent the last six months visiting cardiologists with my husband. There are symptoms which could indicate heart problems, but they have to be investigated further to confirm what is going on. The further investigations involve machines; x rays, blood pressure, heart rate and then it gets very complicated with scans and other procedures. As far as I know it's impossible for any doctor to check vital signs without at least some equipment, that's just nonsense.
If sedation is suspected there is a very simple first test. The person concerned must be roused. That simple test was not applied. Had it been and the twins wouldn't respond then other tests would have been required to discover the level of unconsciousness. None of them include feeling backs for breathing or sticking your fingers under noses to feel for breath.
The equipment needed to check vital signs is a thermometer, a sphygmomanometer, and a watch. Though a pulse can be taken by hand, a stethoscope may be required for a patient with a very weak pulse. There is no evidence that any of the twin's vital signs were checked.