Nazis hated IQ research
Your friend who says IQ research is a Nazi thing? He's wrong.
Pseudo-intellectuals of this day and age love to characterize IQ / intelligence research as "Nazi pseudoscience", and to smear IQ researchers as Nazis.
So, what is the actual truth of the matter?
As you can see, actual Nazis from the Third Reich were very worried that intelligence research would “be an instrument of Jewry to fortify its hegemony” and outshine more properly Aryan values like “practical intelligence” and “character”.
Whenever someone tells you that they "don’t believe in IQ" or that "IQ is Nazi pseudoscience", consider calling them out on perpetuating discredited Nazi ideology.