بسم الله الرحمن الرحيم
(Fatwa: 1178/1131/N=9/1434)
(1) As far as I know, there is no Hadith stating any virtue of death on 27 Rajab and 15 Shaban. But it is established that a person who dies on Friday Allah exempts him from interrogation of munkar nakeer (angels) and protects him from the punishment of grave:
عن عبد اللہ بن عمرو قال: قال رسول اللہ صلی اللہ علیہ وسلم: ما من مسلم یموت یوم الجمعۃ أو لیلۃ الجمعۃ إلا وقاہ اللہ فتنۃ القبر (رواہ أحمد والترمذي وقال ھذا حدیث غریب ولیس إسنادہ بمتصل، مشکوۃ ص 121(
(2) If he did not spoke after he recited Kalimah, it will be considered his last words. May Allah forgive your father and other Muslim men and women who died! May He grant them peace and tranquility!
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband