65 y/o passed away unexpectedly. when found lips were blue, slight pulse in wrist. emt couldnt bring back. could this be heart attack? would lips turn blue?

Yes. That is central cyanosis, a sign of grave insufficiency of circulation. Cardiovascular collapse was most likely caused by either a massive heart attack ( acute myocardial infarction) or cardiac arrest caused by ventricular tachycardia terminating in ventricular fibrillation or terminal cardiac standstill.

Lip cyanosis is relatively common in life threatening conditions, a heart attack remains possible, but blue lips are by no means diagnostic for a heart attack.

A heart attack is one explanation, another one could be a large pulmonary embolus.