William Henry Brown was born on 22nd Dec 1868 in Paddington, Middx.
I believe he enlisted in the army prior to the 1st world war but died in India possibly Rank Sergeant Major.
His wife also died in India and they had one daughter called May Alicia Brown born in 1893.
Assuming her parents married before her birth the father William Henry will have been aged 25 or under when she was born. There is no way he could have reached the rank of Sergeant Major by that age so if that part is true, it must have been later.
I can't find any information On William Henry Brown whilst serving in India. I have an extensive list of possible marriages in London but have not sent off for any as of yet, taking into account that William and his bride may have married in India.
FIBIS (as suggested by nannyjan) only brings up two possible marriages but they are well after May's birth so seem unlikely. For completeness the marriages are:
1) 18 Jan 1905 at the Presbyterian Church, Meerut: William Henry Brown age 30 bach Asst Military Surgeon, father James Henry Brown to Jane Smales 33 widow, dip midwife, father William Few
2) 5 Apr 1905 at the Wesleyan Chapel, Popham's Broadway, Madras: William Henry Brown 62nd Coy Royal Garrison Artillery to Clarissa Mary Haller daughter of Dr and Mrs WH Haller. (Groom's surname also spelt Browne in one transcription)