What is the standard way of “counting deaths” for a disease that can be co-morbid? Does the method chosen differ from other countries and diseases? Strictly s

What is the standard way of “counting deaths” for a disease that can be co-morbid? Does the method chosen differ from other countries and diseases? Strictly speaking, no one does of HIV virus, they die of opportunistic infections made possible by AIDS. For COVID, the disease can kill you, as well as make it easier for other things to kill you. If you die of a heart attack while COVID positive, on a ventilator, with super low blood O2 readings, did you die of a heart attack, or did you die of COVID? Is there any reason why your death must be limited to a single disease for statistical purposes? You say that counting COVID deaths this way is dubious, but is it out of line with regular epidemiological practice?