RE: missionary hospitals…'Sisters'…'Brothers'.
Sounds like medically trained nuns and monks(?) retaining their non-nurse titles.

Could be... but in UK, nurses are so called Sister-- or they were. just as medical doctors and surgens are called mister.. (Mr. not Dr. as they are in US)

but most everyone knows the proper initals, tacked at the end of a name that mean Member of Royal College of Surgens, (yeah, i could have looked it up...but so can you)--something akin to US "board certified"-- where as in US, a goodly percent have no idea what board certified is.

a recent article about health care addressed nursing issues. some hospitals no longer identify Registered Nurses as R.N.'s, and many patients in hospitals are "treated" by health care aides with 4 to 6 weeks of training..

patients might call for a nurse, and get an aid, instead.

(fine of you just need the bedpan, but not so good if your i.v. is coming loose.)