zita,
one of the reasons is that they feel scare, so normally they dun dare to ask for things. Even to the extend on food n fan. But sometimes is communication, alot of maids will say yes mum, yes mum, but doesn't understand a single thing from u.
But at least make known to her, that she can on the fan when she sleeps. Tell her to take enough food, and there is always bread available should she feel hungry.