As a buyer in California, the seller or agent, if they know, are required to disclose the death of an occupant in the home within the last three years. If asked directly if they know about any death in the home, they should answer honesty.
A Realtor may not know the history of all occupant of a home. A second or third or subsequent owner may also not know about all events, including death that may have occurred in the home.
But I have a question for you. If you were dying of cancer or another terminal affliction would you rather die at home in your bed surrounded by all that is familiar to you and your loving family or would you prefer to die in a medical institution?