Question Summary:
Replying to the salaam of a Kafir

Question Detail:

 
Some time non muslim brothers used say Salam to us; so can we reply them as "walekumussalam wa hidayatullah" ( may Allah SWT give you hidayat) or any similar words (please suggest)

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
 
If a non-Muslim gives Salam then it is permissible for a Muslim to reply with the words "وعليك" (and upon you). However, it is impermissible to initiate Salam with a non-Muslim.[1]
 
And Allah Ta’āla Knows Best
Saleem Ibn Sajawal Khan
Bradford, UK
Student Darul Iftaa

Checked and Approved by,
Mufti Ebrahim Desai.