It's difficult to think that someone could live in todays modern world and not know what racism is. Franz Fanon in his book, Black Skin, White Masks, describes racism as subjecting the black man (as a type standing for all under racist oppression) as:
a zone of non-being, an extraordinarily arid and sterile place ... [where] black is not a man ... [and mankind] is digging into his own flesh to find meaning.
to which his reply is that the first thing that the black man wants to say is no.
No to the degradation of man. No to the exploitation of man. No to the butchery of what is most human in man - freedom ... [And above all] no to those who want to build a definition of man.
So perhaps you could begin by giving this book to your friend... but it is rather strange that your friend says:
"he doesn't know what it [racism] is and doesn't admire it either"
Why would anyone bother to admire or not admire something that he doesn't understand? This makes so little sense that it leads me to suspect that perhaps there is no rationale here, except the rationale who wish to misguide with malintent - and so he's pulling your leg - or you are pulling ours. Perhaps he does know what racism is, and does actually admire it, but knowing that this is politically incorrect, he has decided to say exactly the opposite of his true feelings because he doesn't want to own up to it in public.
You're in position to find out - so I'd say: ask him some tougher questions.