(1) The fidyah of sawm is half sa’ (1.633 gram) wheat or its price or to feed one poor man to his full stomach two times.
(2) Yes! It may be given.
(3) It is not necessary to give every day. After the fast starts, the fidyah of the whole month may be given in advance.
(4) You may give it. However, it shall be necessary to explain so that the amount of the fidyah is spent in its place.
(5) It may be given. It should be noted that the concession of fidyah is for very old age person who is unable to observe fast at present and in future and even he cannot observe the fast in the shortest days of the year. In case someone turns healthy after paying off the fidyah and his health is restored and he becomes able to fast then his fidyah shall be null and it shall be mandatory for him to make qadha of those fasts.
Allah knows Best!
Darul Uloom Deoband