I used to think that Ella's constant request for letters was a bit over the top. But now I realize that they were for her a life line. They are her only source of information, her only source of hope. Also, I think I mentioned this before, they were a sign to the Nazi censors that someone somewhere cared about her and about what happened to her. As a vulnerable Jewish woman living by herself, having a handful of letters coming from around the world, especially America, may possibly have given Ella even a thin shell of protection. I don't have anything to back this up, but I get the impression that Ella is asking for letters for many reasons, so of which we may not know.
I love that Anni visits Ella. When we visited with her in Germany in 2013, she didn't really remember Ella very well. I wish she had. Ann was also mentally a little bit off, I believe the war and its consequences did significant damage to her soul. She was not a whole, healthy person. She had become estranged from most of her friends and family. I think she always had that strong personality, but obviously not so strong or disoriented when she was with Ella. She provided Ella with a lot of comfort. I think some of the comfort she offered was that she was a very real connection to Opa. Ella saw in her that same adventurous and inquisitive spirit. For Ella- visiting with Anni and talking about Opa might have been as close as she could get to the feeling of being with Opa.
I remember something similar to this happening to someone I know. My little sister's very dear friend was killed by a drunk driver when she was in middle school. Her parents were completely devastated. But I remember they wanted to spend time with their daughter's friends. My mom marveled at how they could do that, she thought it would be too hard for her if she were in their place. But then she said maybe it was because it was the closest they could get to having even just a part of their daughter near them again- in the memories and behaviors of these middle school kids.
I wonder if that was how Ella felt about Anni when she visited, and Gisela.
Until Ella sees her children again, she will continue mothering them from afar- critiquing their poses and shirt choices. If she were any different, I think it would feel inauthentic.