I think him approaching OCSO speaks volumes -- maybe a whole library full -- about what the evidence even way back then, a fraction of what we have now, indicated to him. And it wasn't that his client was going to be proved innocent.
Actually, I think it was before we really had any evidence back from anywhere. he wanted immunity for them to talk to her.
Possible that he was still believing her BS stories...
I never thought he really believed her, etc... Until when the really strong evidence came back, and he had to go to the hospital. How he seemed to need comfort when the baby was found. He rushed to KC to comfort her. But she reallyl didn't need comfort because she found out her baby died. She needed it because she was in trouble. JB might have finally "got it." Most likely hard to accept.. but still...