My dad could not fast this year in the Month of Ramzan due to poor health conditions. Please let me know what kaffara is applicable for the Entire 30days. We intend to Pay it to the Miskeen please let me know how would I calculate the amount.

If he is an old man, you can pay the fidyah immediately after the month of Ramadan.
But if his breaking the fast was due to illness, then the fidyah should be paid before the coming month of Ramadan.
The amount of the Fidyah is 22.5 kg of rice, wheat or dates for the whole month (750 g per day).
Food should be given, not cash