Quote Originally Posted by translations.nm.ru
Mozes, in Russian, we try to spell foreign names in such a way that they are pronounced as close to their original pronunciation as possible. If you are an Arab and your name is Musa, it is Musa in Russian. For example, the name of khalif Musa Al Hadi is spelled as "Муса" (Musa) in Russian.

An English-speaking person whose name is Moses would be Mozes in Russian. A Spanish-speaking person whose name is Moizes whould be Moises or Moizes in Russian. A modern Hebrew speaking person called Moshe would be Moshe in Russian (e.g. Moshe Dayan) A person calling himself Moishe or Moisha (which is the Yiddish version of the same name) would be called Moisha/Moishe in Russian. See how it works?

The biblical Moses (the person who led the Jews from Egypt) is traditionally called Moisey in Russian. The reason that is it so different from its Hebrew original is that it came to Russian via Greek translations of the Bible.
It depends if he wants a straight transliteration of his name, or wants to know the Russian variant of the name.