Head Injury, No Sign Of Trauma Or Bleeding, Lead To Death, Had Shortness Of Breath, Fatigue. Inconclusive Autopsy. Heart Attack Or Brain Injury?

hi my boyfriend passed away a week ago,it is his birthday today im going out of my mind i need to know how he died as his autopsy report is still inconclusive atm!!...until further tests will be taken which is going to take 6-8 weeks....we was at home he was fine we went to bed as usual at 11pm he woke me up and asked me for some co codomols so i gave him x2 and a glass of water he said he was hot so i put the fan on for him and went back to sleep...i later woke up to a bang down stairs which i lept out of bed and found him behind the door gasping for air with a slight cut on his head,he made a really loud screaming/moaning sound a sound ive never heard before,i immediately rang the ambulance and started doing cpr on him for over 20 minutes ,he did breathe twice but then stopped .he did complain of chest pains 2 days before this but was fine when i got home and refused to go to the doctors.he would be 33 today i just dont understand it. he wasnt bleeding apart from the lil cut on his head but when the paramedics tried to resusitate him for over 40 mins he was bleeding from his mouth why was this? and what do you think he died off? the coroner said there was no sign of trauma to his head or brain so it must be an underlying problem. i have just recently found out his family have a history of heart problems. please help he left his 6 month old daughter im so empty i just need answers .and do you think he was still alive when i was with him? thank you