What indication do we the readers get that Ray realizes that Ruth is actually Susie ?

I never got the sense that Ray felt Ruth was Susie. When Ruth and Ray go to the sinkhole, they are unknowingly going to Susie’s grave. The closing up of the sinkhole is symbolic of Susie’s finishing her time watching the people she knows on Earth. The sinkhole is personified in the newspaper article—it has a throat, and later it “swallows” cars. Ruth is fascinated with it as a greater power. Again, Susie brings in the image of the safe that her body rests in—she actually does feel safe in there, because she knows her body is protected from moles.