I found this. Seems it differs by state so your friend may want to look into your specific state law regarding death and selling:
Material Facts
Material Facts are commonly referred to as anything that would affect the buyer's decision to purchase or the price and terms the buyer offers. In other words, if you have knowledge about a defect, it should be disclosed. In California, sellers are to notify buyers if a death has occurred on the property within the last 3 years. Some buyers are creeped out by knowledge that a
seller died in the house.
A seller once asked me if she should tell the buyer that her husband died in their bedroom five years ago. Although the law doesn't require it, because the death occurred outside of the three-year window and because the buyer did not ask about it, I suggested she disclose this to the buyers, and she did. Moreover, if she had chosen to withhold this information from the buyer, I would have had to disclose it because now I had knowledge of a material fact.
Causes of Death
Many home buyers are fine with news of a death occurring in the house as long as it wasn't violent or gruesome. There are also buyers who believe homes are haunted by former occupants who died in the house. If you have specific details, you might want to consider sharing it with the buyer unless it pertains to AIDS. Check with your local laws and a real estate lawyer for advice about deaths surrounding AIDS because in some states, AIDS falls into a protected class and could be subject to discrimination claims as well. There are times you're darned if you do and darned if you don't.