faire mal

Question

Elle va faire mal à lui. Why this is not correct? can't understand.

Accepted Answer

Bonjour Jagoda,
When the indirect object of an infinitive verb is replaced by an indirect object pronoun, the indirect object pronoun goes in front of the infinitive verb it is the object of:
elle fait mal à Paul -> elle lui fait mal 
elle va faire mal à Paul -> elle va lui faire mal
See link here: indirect object pronouns  -  position-of-object-pronouns-in-sentences-with-infinitives
I hope this is helpful.
Bonne journée !

Answer

Because lui is already the indirect object pronoun and hence includes the preposition à. The correct answer is: Elle va lui faire mal.

Answer

I understand that when the noun is replaced by a pronoun, it somehow includes the à, but why is there a du in the answer:   Elle va lui faire du mal.  ?  Shouldn't it just be Elle va lui faire mal?