A lot of the data on the Internet are indexes to other records, and researchers can use the indexes to locate the original records. They need to look on the Internet for the source of the original records. Oftentimes researchers post information on the Internet without citing where that information came from. ET Doing medical family history is an important use of genealogy. One of the best sources for medical information are death certificates.
Death certificates are public records in most areas.
In some areas they won't release death certificates for 10 or 20 years or more. So they're available for older, deceased relatives. The death certificate will list the cause of death, as well as complications to the cause of death. Older death certificates do not always use current medical terms. Researchers can find medical dictionaries in the library as well as some on the Internet.