How can one overcome intense grief over the loss of a mother, and are there signs that indicate the deceased's good condition after death?

One must be patient and seek reward from God during calamities, for Allah Almighty has prepared a great reward for the patient. The greatest calamity was the death of the Prophet, peace and blessings be upon him. The righteousness of the mother, the love of people for her, and their testifying to her goodness are signs of a good ending, for if Allah desires good for His servant, He utilizes him in righteous deeds before his death. And whoever is patient when his beloved from among the people of this world is taken, his reward is Paradise. And whoever is afflicted by a calamity and says: "Indeed we belong to Allah, and indeed to Him we shall return. O Allah, reward me in my calamity and compensate me with something better than it," Allah will reward him and compensate him with something better than it.