I'm not sure Malhar would've been able to work with and stay around Pawar if the latter had accidentally "killed" his wife, even if he did it just in defense and by mistake. Instead Pawar is the only human Malhar still seems to be able to interact with. I do think that Pawar, like in the naxals track, checked Malhar's gun and realized he couldn't have been the one to fire at Kalyani,and told Sarthak the same. Malhar by then probably wasn't in the state of mind to think right and was ready to accept punishment because he felt guilty for how everything went so wrong and both Kallu and Pillu died.
I think he's not disclosed what he and Sarthak found out about who shot Kalyani and who was in on the plan because someone from her family was involved in the plan along with Trilok (that's the only reason CVs had Nal come back and die) and he knows that, with Pillu and her bio-parents dead, Malhar apparently married to someone else, her family and Anu are the only thing she has left... showing her their real face will only further break her, and she's barely managing to keep the pieces together.