The meds thing may be correct. He was questionably homeless, so some kind of drug might have been correct
So all homeless people are drug addicts?
That bothered me a little bit because I understand where you are coming from as some homeless people become that way because they are not top-shelf members of society, per se, however some have breakdown or are vets with severe PTSD and end up that way not out of choice.
Now that I vented on the social phenomena, I would have to say, given all the facts that this guy was diabetic and currently considering a mild to moderate hypoglycemia as he appeared lethargic and almost intoxicated without the distinct presence of ETOH. The AMS along with the weakened vitals would also back up this theory.
Rx meds is another viable option, did you see his pupils by any chance, if it was Rx meds (somebody elses Rx for example) than the odds are it was some kind of opiate or benzo and he probably would have pinpoint (or at least smaller than average) pupils with delayed reactivity. Remember your opioid triad as he already has respiratory depression and loss of consciousness, the only other thing, which I didn't see anything about was the pupils which should be taken into consideration in the assessment, if pupils were pinpoint the triad would be complete and the odds would point to an opiate overdose.
Finally, perhaps he is narcoleptic and if in decent shape would explain the low resting pulse, this one is more far out than the others but still a possibility, even if not narcoleptic he may have been taking a nap along with a naturally low resting pulse which means that the level of consciousness would have needed to be taken more into consideration in order to determine a proper dx.
Of course there are other things but I would take the evidence into fact and have to side with hypoglycemia or potential overdose (opiate more than likely as per above).
Does anyone else have a take on this?