Do Ns hang with Ns?

If so, how does this work? My N had a friend who tried to intervene and mediate countless times during the abuse. He later ended up trying to date me after it was over. Yuck! I told him countless times to leave me alone. I think he was testing me as N did to see if I'd bite. Who dates their exes friends? Gross!!!! I told him he was trash and blocked his number. I'm beginning to think that he may also be disordered because he knows all Ns vices and witnessed his physical abuse toward me yet now they're back thick as thieves. He claimed their friendship was over during the time he was trying to bait me. Yeah right! I just can't see what decent person would want to hang around someone like a N especially if they've seen ther true self.