I find Judith's work still relevant. It shows how private experiences and public traumas share "fundamental similarities of disempowerment and denial".
I think the only thing that may have majorly changed is that its focus is upon integration whereas those who work with DID patients can now accept a more congruous living "with" DID rather than "curing it and obliterating it."
For the patient I think Getting Through the Day by Nancy J Napier is good. Any of the other books (including Judith's above) may be more on the T level and not necessarily good for the DIDer to go through alone (such as The Courage to Heal and it's workbook should be done with a T, imo.)
There isn't much else to say that hasn't been said in other threads over the years...
but maybe a reminder to provide avenues of expression for the inner child...depending upon the age and likes/dislikes...coloring books, craft items, plushies, and other comfort items are important.
Also important is to journal, and allow the child part(s) to participate however possible, and to reassure that they served a good purpose that helped you to survive/thrive but that it has changed and they are needed in another way now. Letting them know that things have changed and you are safe (truly you must be to work on healing) now.