  We explore the possibility of a single generation of $keV$ scale sterile
neutrino ($m_S$) as a dark matter candidate within the minimal extended seesaw
(MES) framework and it's influence in neutrinoless double beta decay
($0\nu\beta\beta$) study. Three hierarchical right-handed neutrinos were
considered to explain neutrino mass. We also address baryogenesis via the
mechanism of thermal leptogenesis considering the decay of the lightest RH
neutrino to a lepton and Higgs doublet. A generic model based on $A_4\times
Z_4\times Z_3$ flavor symmetry is constructed to explain both normal and
inverted hierarchy mass pattern of neutrinos. Significant results on effective
neutrino masses are observed in presence of sterile mass ($m_S$) and
active-sterile mixing ($\theta_{S}$) in $0\nu\beta\beta$. Results from
$0\nu\beta\beta$ give stringent upper bounds on the active-sterile mixing
matrix element. To establish sterile neutrino as dark matter within this model,
we checked decay width and relic abundance of the sterile neutrino, which
restricted sterile mass ($m_S$) within some definite bounds. Constrained
regions on the CP-phases and Yukawa couplings are obtained from
$0\nu\beta\beta$ and baryogenesis results. Co-relations among these observable
are also established and discussed within this framework.
