The existence of right-handed neutrinos follows from theoretical consistence of the recently suggested electroweak symmetry breaking model, based on dynamical flavor gauge symmetry breaking. Only finite number of versions of the model exists. They differ by the number and the flavor structure of the right-handed neutrinos. We choose for inspection one of them, the non-minimal version with right-handed neutrinos in sextet flavor representation, and at some points we compare it with the minimal version. We show that a Majorana pairing of the sextet right-handed neutrinos is responsible for the flavor symmetry breaking, and the seesaw pattern of the neutrino mass matrix naturally arises. The dynamically generated neutrino mass matrix spontaneously breaks the lepton number and the chiral sterility symmetry of the right-handed neutrino sector. As a result spectrum of majorons, neutrino composites, manifests. We study main characteristics of both massive sterile neutrinos and majorons which show their relevance as dark matter candidates.