What do you mean with "correct spelling"? Spelling of the name in Latin characters? That's difficult for Chinese names, as they are written in Hanzi, Chinese characters, and every writing with Latin characters can only be an approximation, and as an added bonus is language dependent - an English transliteration of a Chinese name is sometimes different from e.g. a German transliteration.
I think things can only be cleared up if the Hanzi used to write the name of your cousin become known.