Sorry for your loss
I always find talking about death sensitive, and due to my characture and probably because spanish is my second language, I have been told I come across "too direct" sometimes in the latin culture. So, I am looking for "not so direct ways" to say "I am sorry for your loss" or some other way of acknowledging you care about thier state of mourning.
Lo Siento por __________________
Lo siento por su pérdida. or Lamento su pérdida.
Or you can just say (more formal):
Mi más sentido pésame.
Looking sad and saying "Que Dios le (te) bendiga" will tell them in a round-about way that you wish them blessings in their time of need.