"Sleep is one sixtieth of death" [Talmud, Berachot 57b ]:

 The homeopathic remedy arsenicum [album] may be indicated [fitting ] whenever there exists a strong fear of death.

As sleep is experienced as a "bit of death"[ one sixtieth of death] arsenicum may help in certain sleeping problems.

If a baby is very agitated, restless and fully awake after midnight [something like from 12.00 to 2.00] and can't be put to sleep] the baby may need some arsenicum.

This is especially true if the mother had to deal –lo alenu-with dead of family/friends during the pregnancy