Il lui faut une voiture

DH, 

" Il faut " is an impersonal verbal expression using the impersonal pronoun ' il ', which has no role in determining the gender of ' lui '.  The use of indirect object pronouns to 'personalise' the impersonal expression is covered in the lesson you linked. 

"Lui" as an indirect object pronoun translates as ' him ' or ' her ' in English.  The translation is correct - as the ' writer ' knows they were referring to a female needing a car.

 https://www.lawlessfrench.com/grammar/impersonal-verbs/

 https://french.kwiziq.com/my-languages/french/glossary/3

 

 

 https://french.kwiziq.com/my-languages/french/view/710