Do the mentioned signs—my mother's death on a Friday, after Dhuhr prayer, while she was in a state of ritual purity (wudu), during her sleep, uttering the Shahada before her death without suffering, and her burial in the family plot—indicate a good ending (husn al-khatimah)? And is informing people of this considered envy (hasad)? What can I do to cope with my grief? And what are the deeds that can be dedicated to her?

Dying on Friday, uttering the Shahadah (definition) at the time of death, and fulfilling the obligatory duties before death are signs of a good ending. As for people's words, you should think well of them and interpret them as congratulations. A Muslim is rewarded for patiently enduring a calamity, and it is better for him. It is also considered among the reasons for entering Paradise, and it entails Allah's companionship and love for those who are patient.