I say "is" to have agreement of the singular "none" . my son, says it should be "are" because "them" is plural.
two points to settle
1) is "none" singular?
2) is "them" the object of the preposition, hence not even relevant to the discussion?
A. According to the Gregg Reference Manual, "none" can be singular or plural, depending on the noun [or pronoun] to which it refers. In formal usage it is still considered singular; however, in general usage "none" can be either singular or plural.
Although "them" is an object of a preposition, it is the word to which "none" refers.
In formal usage, it should be, "none of them is going." In general usage it is acceptable to say, "none of them are going."