Alice Miller, using psychoanalytic terminology, in her books (e.g. Though Shalt Not Be Aware--please Google for exact title), speaks at length on this subject. (Her books also offer a in-direct comment on the early origins of psychology that were male dominated, and protected the male abusers needs for denial. My abusers were male and female, and the books did help me understand the origins of authority figures asking people to not believe their memories.)
After reading those, and integrating that knowledge with accountable, non-violent communication, and Jungian Psychology, I worked out my own way of dealing with the 'believe vs don't believe' flashbacks, that are triggered in every day life.
I work with flashbacks 'as if they are real', since I DO REALLY experience them. For that reason, I personally don't believe in discrediting a perception/experience of mine, that is presenting itself, for me to process.
Truth (absolute) doesn't really exist, true memory doesn't really exist (research at this time is written from the framework that says memory isn't reliable-since we filter realty through our own perspective (victim, victor, etc.).
What made sense to me and my therapists was to work through the memories, as they were MY truth, and as if they were a vehicle for me to learn from, and become empowered by, through the learning process.
At first I wanted to discredit my flashbacks because they were contrary to the 'false truths' that I wanted to believe.
After I worked on my perspective, the flashbacks greatly reduced, and nightmares stopped. Interestingly enough, through time, relatives shared that they had witnessed various abuses that I thought were my memory, alone.
The reason accountability serves me, is that many people do not recognize their behavior as abusive, and asking them to do so, is also self-incriminating (for them), for which many people will, themselves as abusers, disassociate and deny. Hence, it can be self-defeating to ask anyone to agree with a memory of mine. Family members are often loyal to upholding family honor, rather than seeing the truth.
Good luck on your quest!