A ruptured aorta artery can come on incredibly suddenly and, once ruptured, can be enormously difficult to treat effectively within a sufficient time scale. The patient can lose a huge amount of blood in a very short space of time, often without even realising there was anything wrong with them. This means that it is one of the most deadly ruptures that a human being can experience and it is almost always fatal. Therefore his death could probably not have been prevented.
Even assuming that humans have free spirit and control over their decisions, death is still unavoidable. It is the one trait that every baby shares. Are there life choices that Mr. Thicke could have made that would have prolonged his life beyond 2016? Sure. However, who knows where some of those life choices would have taken him. Maybe he would have already been dead.
He could perhaps have forestalled death a little longer with preventative care and good fortune, but even actors cannot prevent death. When your body is worn and done, you will die. If he had survived this heart attack, something else would eventually have claimed his mortal being. Just a reality of 21st century medicine, really.
Even though modern medicine has come a long ways, it's impossible to know when and where a heart attack is going to strike. It's hard to know what the warning signs are. Two people could live the same life and one could have a heart attack at 40 while the other could live to 90 without problems.