According to "Dear Abby", most NT'S would prefer a combination of silence and Nonverbal understanding. Of course, this is much more difficult for people on the Autistic spectrum because of the difficulty in interpreting body language. You also don't want to appear "unemotional" because then everybody will see you as a "cold-blooded" robot. It depends on the person though. Some people won't mind a few words said, but it's not like it will do a lot of good.
I'm just baking up Lightning88's advice and also adding advice given from Dear Abby. It's best to just leave it with what Lightning88 said, "I'm sorry about your father."
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Uninvention Convention