heart valve and triple by pass

hello, i am devastated..my dad was 76 when he had a triple by pass and heart valve replacement at cornell medical center in newyork..one of newyorks finest....he was recovering beautifully for 10 weeks..all through the recovery he had no appetite and was very nauses..they said this is common with by pass, 666- 6days in the hospital, 6weeks to recover and 6months to be normal again..well the 11week he saw his internist and his pressure was 70/54. he was very nauses and dizzy, the internist sent him home sayin to take  it easy his blood was very thin, he has been monitoring his coumidin level for 3yrs. said his pulse was good and his heart was clear, cardiogram was perfect the next morninghe woke up dizzy and called out my moms name and died....his doctors at cornell have no answers for us..they said he was doing wonderful..on may14 was the bypass and valve replacement, and on july 25 he died...could he have been internally bleeding??? WE ARE DEVASTATED..THE INTERNIST SHOULD HAVE TOLD US TO PUT HIM IN A HOSPITA;L, OR AT LEAST CALL HIS CORNELL CARDIOLIGIST....COULD HE HAVE BEENSAVED..HEARTBROKEN....THE BLOOD ONLY SHOULD PLATLETTES WERE HIGH.?????please help we have no answers...thankyou

[Mukesh Garg, MD]

It is hard to say what exactly happened but a heart attack or abnormal heart rhythm seem more likely than internal bleeding