He is right, The main and VERY significant concern of an opiod overdose is respiratory arrest as all opioids are respiratory depressants varying in strength, you have about 90 seconds after the opioid has slowed your breathing to the point that it ceases to the point your heart does some pretty bad stuff, mostly irreversible. That is all Narcan is really for they’re only try by to reverse the respiratory depression/arrest so the person starts breathing again which is the only truly immediate emergency. When respiratory arrest turns into cardiac arrest it’s pretty much game over unless there is help close by and even then it can be a coin flip Narcan really does save lives the only issue is the very short half life, if they don’t go to the hospital after it wears off, the opioid kicks back in and you can go right back to where you started. Not a Med professional just a 20 year fireman, lots of experience with this