There has been nothing in the show to suggest that Rarity has any family other than her parents and here sister, Sweetie Belle. That does not necessarily rule out the possibility, but it does seem unlikely that she has a brother.
He could be thought of as her adopted brother, but he is not her brother in a biological sense.
Spike
Her name is Zecora.
a spanish person who speaks poor English
She likes him as a friend, but does not appear to have any romantic feelings toward him.
Nicole Oliver voices Princess Celestia in My Little Pony.
Spike has a crush on Rarity.
Spike has a crush on Rarity.
Spike
Spike is voiced by Cathy Weseluck.
My Little Pony 'n Friends - 1986 Spike's Search - 2.5 was released on: USA: 11 September 1987
Her name is Zecora.
a spanish person who speaks poor English
She likes him as a friend, but does not appear to have any romantic feelings toward him.
Carolin Kennedy's pony was named Macaroni. I don't know if her little brother ever had his own pony.
Nicole Oliver voices Princess Celestia in My Little Pony.
The very first episode "Friendship Is Magic- Part 1", all of the Mane Six are introduced and it is revealed that Spike is attracted to Rarity.
Spike and Apple Bloom do not go on a date in any episode. However, the is undoubtedly fanfiction on the subject, which can probably be found on the fimfiction website.