Victor's mother's death?

I believeyou can find that in Chapter 3.

Chapter 3 page 17 Frankenstein:

When I had attained the age of seventeen my parents resolved that I should become a student at the university of Ingolstadt. I had hitherto attended the schools of Geneva, but my father thought it necessary for the completion of my education that I should be made acquainted with other customs than those of my native country. My departure was therefore fixed at an early date, but before the day resolved upon could arrive, the first misfortune of my life occurred—an omen, as it were, of my future misery. Elizabeth had caught the scarlet fever; her illness was severe, and she was in the greatest danger. During her illness many arguments had been urged to persuade my mother to refrain from attending upon her. She had at first yielded to our entreaties, but when she heard that the life of her favourite was menaced, she could no longer control her anxiety. She attended her sickbed; her watchful attentions triumphed over the malignity of the distemper— Elizabeth was saved, but the consequences of this imprudence were fatal to her preserver. On the third day my mother sickened; her fever was accompanied by the most alarming symptoms, and the looks of her medical attendants prognosticated the worst event. On her deathbed the fortitude and benignity of this best of women did not desert her. She joined the hands of Elizabeth and myself. "My children," she said, "my firmest hopes of future happiness were placed on the prospect of your union. This expectation will now be the consolation of your father. Elizabeth, my love, you must supply my place to my younger children. Alas! I regret that I am taken from you; and, happy and beloved as I have been, is it not hard to quit you all? But these are not thoughts befitting me; I will endeavour to resign myself cheerfully to death and will indulge a hope of meeting you in another world." She died calmly, and her countenance expressed affection even in death. I need not describe the feelings of those whose dearest ties are rent by that most irreparable evil, the void that presents itself to the soul, and the despair that is exhibited on the countenance. It is so long before the mind can persuade itself that she whom we saw every day and whose very existence appeared a part of our own can have departed forever—that the brightness of a beloved eye can have been extinguished and the sound of a voice so familiar and dear to the ear can be hushed, never more to be heard. These are the reflections of the first days; but when the lapse of time proves the reality of the evil, then the actual bitterness of grief commences. Yet from whom has not that rude hand rent away some dear connection? And why should I describe a sorrow which all have felt, and must feel? The time at length arrives when grief is rather an indulgence than a necessity; and the smile that plays upon the lips, although it may be deemed a sacrilege, is not banished. My mother was dead, but we had still duties which we ought to perform; we must continue our course with the rest and learn to think ourselves fortunate whilst one remains whom the spoiler has not seized.