à qui vs. auquel form of relative pronouns

Question

I have read other explanations of à qui and the auquel forms of the relative pronouns and they are not interchangeable;  à qui  is used for people and the auquel form is used for things and animals.  I think this distinction should be corrected in your lesson and on the tests.

Maarten Kamp · Accepted Answer

TM, 
you haven’t given your references, so it is impossible to comment on them. Can you post the links or quotes ? 
However, Larousse and wordreference disagree with them, as does the Académie-Française in its discussion, and Robert. 
As far as I am aware the lesson is quite correct - it seems unlikely the native speakers here are getting this wrong. My wife is a native speaker, qualified bidirectional English-French translator - she also agrees with the examples and comments on usage as they are given in the lesson. 
It is correct however, that ‘ à qui ‘ can only be used with living things ( as noted in the lesson ), so in that sense the forms are not completely interchangeable. 
Of course, there is nothing wrong with deciding for yourself to use only ‘ à qui ‘ in reference to people, and the ‘ auquel forms ‘ with everything else, but it is more restrictive than necessary according to the lesson, and the references linked.
See link below to Laura Lawless site as well.
 https://www.larousse.fr/dictionnaires/francais/lequel/46743
https://www.wordreference.com/fren/auquel 
https://www.dictionnaire-academie.fr/article/A9L0590
 https://dictionnaire.lerobert.com/definition/lequel
 https://www.lawlessfrench.com/grammar/relative-pronoun-lequel/