Salam my beloved Shaykh,
Could you please advise if it is acceptable to sadakah a Fatihah to a deceased non-Muslim when paying respects in a wake?
A`udhu billahi min ash-shaytan ir-rajeem
Bismillahi ‘r-Rahmani ‘r-Raheem
You may do so, and we shall leave everything else to Allah Almighty who is Most Wise of Judges over the deceased.