Symptoms of heart attack. Of his death?

My dad passed away at early morning 3.30 am. we assume that it should be a heart attack but he did not get even a drop of sweat. does all heart attack results in sweating of body? during his last moments, his tongue went on one side and he was biting it. he passed urine in bed itself and had 2 deep breaths after that no movement at all.. saliva came out of his mouth and never opened his eyes.. he just left 2 last deep breaths without opening his eyes and then thereafter there was no pulse at all.. cpr did not help.. previous 2  days he was telling something was blocking his chest like a fleghm and was not able to breathe at all. he even felt cold symptoms. what would be the reason of his death? he was afraid to come to doctor for diagnosis.. we are in atmost sorrow accompanied by confusion. please help.