  We explore possible signatures of the interaction between dark matter (DM)
and massive neutrinos during the post-reionization epoch. Using both Fisher
matrix forecast analysis and Markov Chain Monte-Carlo (MCMC) simulation, we
conduct a thorough investigation of the constraints and imprints of the
scenario on the upcoming post-reionization and galaxy surveys. Our
investigation focuses on two key parameters: the strength of the DM-massive
neutrino interaction ($u$) and the total neutrino mass ($M_{\rm tot}$), on top
of the usual 6 cosmological parameters. We utilize future 21-cm intensity
mapping, galaxy clustering as well as cosmic shear observations in order to
investigate the possible constraints of these parameters in the future
observations: Square Kilometre Array (SKA1 and SKA2) and Euclid, taking both
conservative and realistic approaches. All these missions show promise in
constraining both the parameters $u$ and $M_{\rm tot}$ by few orders compared
to the current constraints from Planck18 (SKA2 performing the best among them).
Although we do not find much improvement in $H_0$ and $\sigma_8$ tensions from
our forecast analysis, SKA2 constrains them better in conservative approach. We
further perform a brief investigation of the prospects of some of the next
generation Cosmic Microwave Background (CMB) missions in combinations with LSS
experiments in improving the constraints. Our analysis reveals that both SKA2
and CMB-S4 + Euclid + SKA1 IM2 combination will put the strongest bounds on the
model parameters.
