I found my most important role in Doctors appointments especially locums or hospital doctors who didn't know Mum, was to translate the questions the doctors were asking so that Mum would give a useful answer.
A key problem with Mum was timeline, so when asked for symptom A she would say yes but be referring to anything from 6 months to 60 years before so, it was my job to get her to focus on what happened yesterday, or at least establish some time frame. In the early days when I was less experienced Mum did actually end up going for exploratory surgery for stomach pains which she described and appeared to be suffering pain from, but the warped time line meant she was actually remembering pain from 40 years before as if it was current.
It is a hard learning curve, but be honest even if it's painful to say the truth, and push whoever you are caring for to give the Dr's a fighting chance at a correct diagnosis. I found the GP's quickly learned to 'pretend' that I was the next patient so she would wait outside, or phone me after the consultation. Hospital appointments were always more complex, the sheer number of people involved in hospital and remote multilayered nature of many treatments means you really have to stand up to keep things on track.