Can the estate of a woman who died be calculated when her only heirs are: the sons and daughters of two sisters who died before her, and the sons of her father's paternal cousin?

If the deceased left no heirs other than those mentioned in the question, then the inheritance is specific to her father's two paternal cousins. The wealth is to be divided equally between them, as they are 'Asabah (agnate heirs). An 'Asib takes all the wealth if he is the sole heir, or what remains after the Ashab al-Furood (Qur'anic heirs) have taken their shares. However, if one of the paternal cousins is a full brother (from the same father and mother) and the other is a half-brother (from the same father only), then the full paternal cousin inherits alone. Paternal cousins from the mother's side do not inherit, nor do the children of the two sisters, male or female, as they are among Dhawi al-Arham (relatives by blood but not entitled to a prescribed share or 'Asabah status). It is advisable to refer inheritance matters to the Sharia (definition) courts for a precise verification of all heirs, bequests, and debts.