It took me a couple of years of encouragement by my T to finally go down the inner child path. It has been incredibly revealing, difficult, deep, digging into the dirt. As it was explained to me, we tap into the frozen, traumatized parts of the mind that need to heal. I have been writing with three parts for six months. I can't begin to explain all that I've learned including uncovering many hard, repressed memories. I have a new understanding of what I endured and the uncovered feelings. And my therapist is walking the path with me. Her insight is paramount.
Does your therapist know about the coach? I would suggest working face to face with your T as it's very intense at times.