الجواب حامدا و مصلیا
The questioner’s father has very good motive, but it is not necessary to perform 2 separate rakats for all of the mentioned matters. 2 or 4 rakats of Salatul-Haaja can be performed after which supplication can be made for the well-being of the living, and however much rakats can be easily perform without any difficultly, its rewards can be dedicated for those who have passed away. This method will be more convenient for the questioner’s father and his objective will also be achieved through it.
And Allah knows best.