If you feel you've lost trust in her, then I think it's a good idea to look for a local therapist. Trust is an important part of the therapeutic relationship, and if that is gone, I don't see how you could effectively work together. And it seems like it went away when she initially moved to be with her grandchild and like you've been struggling with it since then. So I think looking for someone else might be the best option. I'm sorry.