I have a relative who is supposedly faking cancer, but I live too far away to know the truth. My only information is facebook. She spends a lot of time saying that she did Chemo or radiation, then went on a long road trip out of state right from the hospital. She has never lost any hair or been sick or lost a single pound. Is that possible? I don't think so, but I don't know for sure.
This person has a lifelong pattern of lying about everything. So it is either true that she's still lying to gain attention or she's finally telling the truth but nobody believes her (because she cried wolf).
Either way, it's disturbing to watch it unfold, even as a neutral party who is undecided. She seems to have truly upset those who lost a loved one to cancer in the family. They feel quite a lot of rage. They also hate it that she has convinced some people that she is fighting cancer, who fly to see her or send her well wishes all of the time.
So I feel that there is no way to get out of being upset, angry, or perturbed when people lie to and/or discount others. It's hard to watch all the effects this has on people in my family. It's hard to see those who feel anger with everyone, so hurt by the lies and hard to think someone is lying to exploit a terrible disease for attention.
I think for PTSD, it's no different for me with PTSD. I don't like seeing deception. It's also very triggering to be invalidated by those who don't want to believe the awful truths of life.