Three men freeze to death in a friend's backyard and aren't found for three days

Eh, he already admitted to all the previous charges: he supplied them with the drugs, thus indirectly and unintentionally causing their deaths. At least in most States, “murder” implies a deliberate attempt to cause death, which seems like it could be hard to prove based on these facts.

But he could be charged with criminally negligent homicide.

Is that different from what they were originally charged with, “involuntary manslaughter”?

Negligent homicide means you do a thing which results in people dying. You do not even have to have a direct connection to the people who die, you just do something improperly and deaths result.

Right, but to my understanding, that’s also what “involuntary manslaughter” means. Is there a distinction, or is it just a case of different States using different words for the same thing?

There may be slight variations in the elements or phrasing, but both are the same concept.

Aren’t drug dealers sometimes charged with lower level murder when their clients overdose?