The informant can be anyone present at the death, from a doctor, nurse, or family member, even strangers.
Family members can give more reliable information but necessarily accurate.
The same man gave details on both his father's and his mother's deaths in my research and the ages of their children on both certificates were a bit off!!! The order and names were right.
Sometimes an informant may be a previously unknown child of the deceased. This is really an exciting find. Siblings also prvide other exciting finds.
But I have two certificates where nothing is recorded, one says married particulars unknown (this man was a convict who had served his sentences married and moved states) the other died in a asylum and it just says particulars unknown. I hope to teace the asylum records oneday as these often have inforamtion which is not recorded on the death certificate.
patience is the key!!!
Robyn