I was reading this thread last night at home (so not logged in) and was struck by MrsDeVere looking for a gym. Could you poerhaps see what the going rate is next door??!! 
But I am also very very struck, in a very "well done that lad" way, by the OPs DNephew and the way he stuck up for himself.
I am a reasonably lay person in terms of the medical world, but my mum is a former nurse (gave up on marriage), I've been through a fair few things myself and with my siblings over the years, I'm a trained first aider since late teens (recently re-did training so more advanced first responder level now), I did science (microbiology and biochemistry) in college, and DD has had a fair few things to deal with over the years (so I am NOT depending on ER and other medical dramas for my knowledge).
I've had various reactions over the years to trying to explain things to medics - I try to make sure I have all relevant info to hand, and give it clearly, chronologically and precisely. Most medics are happy to hear it and ask a few more questions, but I have had young trainees querying "am I part of the profession?" and then utterly dismissing me when I said no (my career is a bureaucrat), and elderly consultants with a very much "I am the highly qualified cons here with more than 30 years experience, so I will decide if you need an extra tear just because I think you should have something done way ahead of schedule when already sore and unnecessary - and I've ignored everything you've said for the past 8 months I've been seeing you anyway" attitude.
I now get DD to explain things clearly too, she's 6, as she can let the medical person know what's wrong as well and it is important for her to be able to discuss what's wrong with professionals in due course. I won't always be there to advocate for her, and I want her doing it herself.
Most professionals I've dealt with are mainly human, but there are still quite a few who have an arrogant streak in them (not saying the fitter did, but there can be an "I'm the professional, I know best dear" with a pat on the head, attitude amongst the medical world, especially when dealing with women or children). And THEY need to know that sometimes the patients are human too, and they might actually know what's wrong with them and what will or won't help them dealing with it day to day, which the professional just may not understand fully.