Several comments (and you are quite right, they ARE general comments):

1) the going into difficult material and coming out to resource/positive material, and then back into the difficult material is a useful and necessary step for some people. Whether one calls it "fractionation" as in the hypnosis literature, or "pendulation" as in the somatic experiencing literature, it helps keeps things from being overwhelming.

2) seeing things in imagination is an important resource for many people. It helps supply experiences that were missed, so for example, nurturing in the minds eye supplies the experience of nurturing that may have been missed. The brain seems to enjoy the experience and benefit from it even though it is fictional.

3) On the other hand, one best not avoid the grieving that needs to occur for the lost years of not being nurtured, the loving parent one didn't have.

4) Finally, if someone knows that it is imagination and not reality, then the person is reality oriented. If someone spends a great deal of time in fantasy, to the exclusion of reality, it may be another form of dissociation. Ones therapist may be able to help sort that out.