Clarification for parts of a sentence
I came across this sample sentence: Le ha bajado la fiebre which translated to her fever has gone down.
My understanding is that "la fiebre" is the subject in respect to which the verb has been conjugated. Additionally "le" here is an indirect object pronoun referring to the girl. Is this correct?
In that case I'm not quite sure how the girl is an indirect object here. Is it in the sense that the fever went down "for her"?
Would it be grammatically correct and convey the same meaning to say instead: "Su fiebre ha bajado"? If so is one way more commonly used than the other?
2 Answers
I believe that your "le" there is what's called the "dative of interest" (which is quite similar to an indirect object). Of course, "down for her" is a lousy translation (since one doesn't say that in English). "Her fever went down.", although syntactically different, is the far better translation.
I can't swear to having heard "su fiebre ..." but it sounds fine to me.
It's probably a similar construction to what happens with body parts - 'me he lavado las manos' rather than using the posessive pronoun 'mis' manos. (Although that's a reflexive construction, unlike your example)
Regarding your suggestion, you would probably be understood and I couldn't say for sure that a native speaker would never say 'su fiebre ha bajado' but I'd bet that 'le ha bajado el fiebre' would be much more common. 
