How do you handle brown noser's?

I work around at least 4 cliques. Most of the cliques have NCO’s (I’m military). Some of the other soldiers pretty much sniff brown all day everyday and act WAY differently around the nco’s then when we’re alone or just soldiers hanging out. One of these D’bag’s is/was/? a friend. Does anybody think I should break off the friendship now before I eventually get into an altercation with him?

Before anybody says, I already brought it up to him about him being “fake” as you would say.