
Muriel G. answered 10/26/20
Professional Archaeologist Teaching Social Science from the Ground Up
If your great-grandmother was a Muslim, you would likely have known about it before her death, as she probably would have requested an imam to be present at her funeral. In Islam it is generally recommended to bury the body as soon as possible, so specifically requesting a wait of three days would be unusual for a Muslim burial. Burying the body at night is also unusual, although not forbidden, in Islam, but it's unusual in general because most graveyards don't like people messing around there at night for obvious reasons. Although I can't say 100% for sure, it sounds like your great-grandmother was just eccentric and not a Muslim. I'm sorry for your loss.