@BrumBoo
The relative would have needed their own hospital bed to have biscuits removed from certain orifices if this had been. That's why I don't work in care though. You weren't being unreasonable at all, not even the 'oh well'.
OP - I've worked in a couple of hospitals. I was warned by a surgeon I worked with that sooner or later someone would make a complaint about me, and that the odds were that it would be
a) totally vindictive
b) from someone I'd gone out of my way to help as much as I could, above and beyond the call of duty
c) not from a very sick person (people who are ill are just so bloody grateful to be taken care of . . .)
d) unavoidable, and, finally
e) about bugger all (as yours was) because people who are looking for something to complain about will find something, or provoke something, or manufacture something.
She said it would be very upsetting (and when it happened it was - and also all of the other points above).
Her other good advice was re:notes. Do them every day even if you have to stay back to complete them. Keep them neat. concise and clear. And most important NEVER WRITE ANYTHING IN THEM THAT YOU WOULDN'T BE HAPPY TO SEE PROJECTED ONTO THE WALL OF A COURTROOM IN LETTERS A FOOT HIGH!
This is because one day you, or a colleague, might be in court - hopefully as a witness - but anything vague or even mildly unprofessional in your notes will come back and land on you with a vengeance. (I should add that this was in the era when medical notes were peppered with Dr. shorthand such as "FLK" - "Funny-Looking Kid". Sounds - and is dreadful, but it meant that there were signs of a possible syndrome that needed to be checked out, but not clear what.)