That's a tough situation to be in. Your grandmother obviously made a decision based on the fact your mom is her daughter, so I wouldn't hold any resentment towards her. In terms of your mom, this might be an ideal opportunity to reset the table with her where it comes to communication and how its delivered. The one thing parents and their kids have the hardest time doing (even under ideal circumstances) is knowing when to change the discussion from adult to child to adult and adult.

As parents we always see our kids as our kids. They can be 6, 16, 26, 36, etc. They will always be our kids. But there comes a time when that delivery needs to change on BOTH sides regardless of the role that we have. Once the child becomes an adult and is out in the world making adult choices, then it becomes incumbent on the parents to cease the micro managing and start respecting the choices their kids make for themselves, whether it matches our personal choices or not. And I certainly understand that covers a large canvas of issues that make it hard to do.

The flip side of that though is the kids need to start looking at their parents as individual adults too. That means the child/parent dynamic must be replaced with a more measured response that illustrates you have reached adulthood, dictating you no longer talk to your mom as you did when you were younger. Throw out emotion and replace with reason. Leave out topics of the past that are sore spots and accentuate a culture of positive discord. If she asks about your therapy, just say, " Mom I really appreciate the fact you worry about me, but I've got this. It's going well. Please trust me to take care of this for myself. If I need to pull you in, rest assured I'll let you know. How are things going with you?" Keep it positive, but deflect it softly back to how she's doing, so she understands there's an investment here, and over time that message will resonate.

Moving out only keeps the conflict alive. This is a great opportunity for you to change that narrative and work on a new dialogue that might be helpful not only for you, but help her in her struggles as well. I wish you the very best in this situation. Its a tough hurdle, but a very common one between adult kids and their parents.