If it helps, in a lot of place "injuries incomparable with life" are sufficient to cease care on a patient.

Still (and this is a general opinion unrelated to any judgement about the OP's story, which I don't hold any opinion on), finding a pulse can be hard for a lot of folks in a lot of situations.

I'm pretty okay with, say, 20-year-old EMT-Bs needing a bit more bureaucracy before they declare me dead. It takes about 90 seconds to place a 4-lead, no shade on those kiddos.