How did Rian die? The Silmarillion and Unfinished Tales simply stated that she laid herself down some mound where Huor was and died. Did she died of food, or did she kill herself?
Rian ... wife of Huor and mother of Tuor; after Huor's death died of grief on the Haudh-en-Ndengin.
To answer your question, her grief was so strong that she pined-away; she simply gave up caring about anything and withered away due to lack of food, drink, and/or shelter.
but I also suppose that Rian didnít saw a chance to raise and support Tuor. It would have been like in other cultures that a woman canít exist without a man.
I suppose having just lost her husband, and seen the hopes of the free people die in a terrible battle, she may have thought there was little hope for the future. I disagree, however, that the culture was such that a woman could not support a child on her own. Her cousin, Morwen, who married Huor's brother Hurin managed to keep her household together even though their lands were occupied by Easterlings. And then there was Haleth, Lord of the Haladin, who managed to lead her to people to safety after the death of her father.