The New Oxford Dictionary of English defines 'needful' as follows:
noun (the needful) what is necessary: I call upon the authorities to do the needful.
It doesn't state that it is Indian English, and I see no reason why I should challenge the authority of the lexicographers.
It is stated on the cover of The New Oxford Dictionary of English that it is the foremost authority of current English. It has 4 million words of text - the biggest single-volume dictionary. It further states that it focuses on English as it is really used in the late twentieth century, informed by currently available evidence and the latest research.
Compact Oxford English Dictionary defines 'needful' as follows:
noun (the needful) informal what is necessary (It doesn't state that it is Indian English)
BNC also accepts 'needful' as a noun and provides an illustrative sentence.
Results of your search (BNC)
do the needful
Only 1 solution found for this query
CLD 831 The one who was born Greek and fluent, had lost his baggage, presumably in transit in London, and wanted action, and seemed to think that young Erlich would do the needful.
If 'needful' is Indian English, the Oxford dictionaries would have stated so. Also BNC will not have included 'needful' in its vocabulary and I would not have been able to find any result from my search under this word.