With testamentary succession, the matter is simple: do what the will says. Religion aside, the Indian Succession Act, 1925 says
- As to what property deceased considered to have died intestate.—A person is deemed to die intestate in respect of all property of which
he has not made a testamentary disposition which is capable of taking
effect. Illustrations (i) A has left no will. He has died intestate in
respect of the whole of his property. (ii) A has left a will, whereby
he has appointed B his executor; but the will contains no other
provision. A has died intestate in respect of the distribution of his
property. (iii) A has bequeathed his whole property for an illegal
purpose. A has died intestate in respect of the distribution of his
property. (iv) A has bequeathed 1,000 rupees to B and 1,000 rupees to
the eldest son of C, and has made no other bequest; and has died
leving the sum of 2,000 rupees and no other property. C died before A
without having ever had a son. A has died intestate in respect of the
distribution of 1,000 rupees.
Then other acts address intestate succession, such as the Hindu Succession Act. If we suppose the will only identifies an executor, then w.r.t. distribution the Hindi Succession Act (etc.) govern the distribution. Those acts are ostensibly specific enough that there is no discretion: except, the law only addresses portions of the estate, and not very specific matters such as who gets the watch and who gets the computer. Indeed, there is a reasonable chance that property is not wholely transferred to a beneficiary, instead the beneficiary gain an interest in the property. There are also related provisions regarding an heir's transfer of his interest in property where other heirs have a "right of first refusal". So in general, the laws of intestate succession remove discretion from the equation. A will could, however, empower an executor to make a decision. The provisions of the will must be in writing.
"Challenging" a will is a specific legal process, not the same as "asking about a will". If a legal petition has been filed, the will is challenged. If a person asks a lawyer "is that really legal; what does that mean", that is not a challenge.