sleep, asleep, fall asleep

Definition:

These terms have figurative meanings relating to death.

To "sleep" or "be asleep" can be a metaphor meaning to "be dead." (See: Metaphor)
The expression "fall asleep" refers to the moment when someone starts sleeping, or in its figurative sense, the moment when someone dies.
To "sleep with the fathers" means to be dead, as one's ancestors are.

In some contexts, the term "to sleep" or "to be asleep" could be translated as "to be dead."
To "fall asleep" could be translated as "to suddenly be asleep" or "to start sleeping" or "to die," depending on its meaning.
note: It is especially important to keep the figurative expression in contexts where the audience did not understand the meaning. For example, when Jesus told his disciples that Lazarus was "sleeping" they thought he meant that Lazarus was just sleeping naturally. In this context, it would not make sense to translate this as "he died."
Some languages may have a different expression for death or dying which could be used if the expression "sleep" or "asleep" does not make sense in the project language.