Re: What we should when ???
Ditto! I say “Yarhamuk-Allaah” to Muslims and “(may Allaah) bless you (with Islam/Guidance)” to Non-Muslims/Kaafirs.
In our beloved Prophet’s :saw: time the Jews would sneeze in his presence hoping he would say “Yarhamuk-Allaah (may Allaah have mercy on you)” to them as was the custom of the Muslims but instead our Prophet :saw: would say “Yahdeekum Allaah wa yuslihu baalakum (may Allaah guide you and reform you).”