Just a bit to add to tthaker's correct answer. Daniel's mother died not only from grief, but also from exposure, probably from pneumonia. The deaths of Daniel's parents have additional health ramifications. Daniel's sister, Leah, who found her mother at the foot of her father's cross, is so traumatized that she becomes agoraphobic (fear of going out of one's home) and suffers other fear-induced disabilities. Although modern readers would probably immediately recognize the trauma to the young girl, the explanation in Daniel's time was that the girl was possessed by demons.
Daniel's aging grandmother also suffers physically because of his parent's death. Forced to work even harder in the fields, gathering the grains left behind by the threshers, she eventually wears her body completely out. Her death is the reason that Daniel returns from the mountain, where he has been holed up with Rosh, to be with her on her deathbed.