this is kind of like what I'm working on presently. I have two T.s-- one marriage one and one individual therapy one. I have been told by both that parts of me are coping like a child and other parts can sort-of cope as adult.

The marriage T., met with me alone once(she specializes in trauma) and she wrote down a list of "child" or old coping skills that I used as a child that worked back then but aren't correct to use as an adult--- who knew!!!
like one I have is "shut down"... when upset.... that's what I did as a child-- since a child in my situation was not heard... but that doesn't work in adult relationships. and another is "don't make waves" when I disagree with something..... that doesn't work well in relationships as an adult, but it kept things, at times, from escalating as a child...

She(the marriage T.) said that I react in "child" mode a lot of times(I'm working on feeling safer in order to cope in healthier adult ways).... or she could have said-- my child parts are taking over-- which they are and that I need to feel safe in order to get the scared child to let go and allow the new adult to cope in better ways--
No matter how it's said it's how it feels to the person struggling that matters. (but just because I have "parts" doens't mean I struggle with DID-- in my opinion...)
Everyone one has parts--such as there could be the "at work" part which can be different than the "spouse" part or the "adult offspring" part, there could alsob be the "playful child" part, the "scared child" part, the "in control" adult part and on and on.... People have many many masks that they put on throughout their day/life. I think that those with trauma might have a few more parts than the average person........

this is all just my views....
I'm not saying anything pro or against DID... it's VERY controversial.... I'd rather stay away from that debate. I think that just because a T. says one has child parts doens't necessarily mean one struggles with DID. I wish T.s would be more careful though how they word things.
(also, I'm not saying you are or are not DID .... that is between you and your T. and not any of my business... so I hope you're not offended.)

best to you

fins