Is intense fear of death and the grave, and feeling distressed by life after experiencing a grandmother's death throes, considered evidence of weak faith?

Fear of death is natural because it is a calamity, and by itself, it does not indicate a deficiency in faith. Rather, remembering it is commanded in Islamic law, as in the hadith: "Remember often the destroyer of pleasures (i.e., death)." Islamic law has also encouraged visiting graves to remember the Hereafter. A Muslim should make their fear of death a motivation to complete their faith and perform righteous deeds, in accordance with the verse: "And do not die except while you are Muslims."