If you notice that an individual has suicidal thoughts they must take it seriously and talk about it with a mental health professional. Although suicidal ideation can be part of grieving, the person grieving needs a professional assessment of the risk and any necessary intervention.
Understand that in the different grief theories, acceptance is the last stage of the grieving process—this stage occurs at different times for each individual; so extreme patience is the most important component of helping someone work through the challenging stages of their abyss.