So you're trying to help someone through system discovery. What to do?
Was talking to my singlet partner, who at this point has, somehow, netted 3 system partners and another highly-dissociative-but-does-not-necessarily-have-a-CDD throughout their life, about what it's like to help us through dissociation and system discovery. I honestly don't remember much of my own behavior and actions throughout my early CDD recovery journey because my dissociation was that bad, and I really appreciate them taking the time to sit down with me and talk about their experiences with me. And I figured I'd share some of their wisdom that they shared with me here, along with wisdom others have shared with me and wisdom I've managed to pick up myself.
Let the person define their experiences however they want. You can offer them example and perspective based on your own knowledge and experiences and offer up wording if they're struggling with explaining something, but avoid trying to deny or "correct" anything, especially early on.
Go slowly, and at their pace. Don't push for them to learn more about their system, don't ask them to go digging for trauma memories (please, god, please don't do this), don't force them to stay grounded for extended periods of time if they can't. Sometimes a gentle nudge here and there can be helpful, especially if you know the person well and know what their limits are or at least know what to look out for, but be careful how far you push and at the end of the day it works better to trust that they know themselves better than you do.
Accept them for who they are, yes each and all of them. Not every member of the system will be all sunshine and rainbows, some parts may even be "cringe" in some way, and especially when dealing with someone with a CDD you're almost definitely going to be dealing with traumatized parts or parts that are otherwise unpalatable in some way. If a part comes forward with an identity or experience you're unfamiliar with, give them the same love and acceptance you would any other part.
Similarly, do not push alters away simply for existing. Many people make the mistake of thinking there's a "true" personality in the system (ie. a core/original, sometimes attributed to the host alter) and thus only want to interface with that specific alter. In truth, every alter in the system is just as real as each other and it's important to treat all of them as valid.
Understand that this is probably just as if not more confusing for the system going through system discovery than it is for you. Realizing you're a system or a part of a system can cause massive identity issues and shifts in the understanding of the self. Be patient with them as they may be experiencing a lot of conflicting emotions during this time.
Check what's helpful for them or what they'd like you to do to help them through system discovery. Do they want you to help point out potential switches? Do they want you to help with grounding? Do they want help remembering things that may have gotten lost in their amnesia? Would they prefer to explore things by themselves (or with just their therapist) with little to no outside help? Every system is different and what may help one system could be detrimental to another.
Above all, take care of yourself and know your limits. Step back if things are overwhelming, set boundaries when you need to. You can be there for your loved one when you're in a better place to help them.