It is a delicate subject and everyone grieves in their own way although the grieving process is similar for everyone, following the same 5 stages of grieving. Denial, Anger, Bargaining, Acceptance & Depression.
Although people have the habit of saying “I know what you are going through I lost my…..” No one really knows what a person is truly going through. Even siblings grieving for the same parent are not going through the same thing and doesn’t really understand each other fully. Since each sibling has their own individual memories, their own individual experiences and therefore are going through their own individual grief and pain.
People also are so flustered when they make their shiva call they don’t know what to say so they say the most stupid and irrational things. If you are the one unfortunately that may be entering this tragic situation please know that this is a common occurrence and the aveilim will compare notes at the end of the night and just laugh at it. Many a visitor has “redt a shidduch to the aveil”. Even thought the nifter or nifteres wasn’t yet even cold in the grave. Many a visitor put in an offer on the home, or offered the name of a good lawyer so the family can sue the doctor for malpractice.
People should know that there is going to be awkward silences at the shiva house and that’s OK. It is not up to the visitors to make conversation. The Aveilim will begin to speak when they are ready.
As far as helping others who are grieving. At the beginning of the process the best thing to do is be a great listener. Be there so a person can share the pain, release the pain, talk out their hearts. Be there to listen, to share, even to cry with another person. When you share the pain you allow them to unburden themselves and lighten the load.
Also please realize that the when a person is grieving they are not their normal selves and their normal chores do not get done. Their children are missing that parent. The household is not being run normally. Ask the non-grieving parent what needs to be done to pick up the slack. What does the grieving person need? What do the kids need to help get the home back to normal.
After a period of time, if the person in pain is not coming out to do normal things, start visiting. Don’t allow them to indulge themselves to be alone in their grief.
Years ago I befriended a woman who had ten children and lost one to leukemia. Since that child had died 10 years earlier, it was always about mourning that child’s death. The kid’s lives were never the same, everything was about loss. Do you know what I told her? I said I can hear your child banging on his coffin yelling “can the rest of you get out of here there is no room for me!!!”. It got to her. I told her it was high time she stopped mourning his death and honor his life! That was a turning point for her.
Hashem has it all figured out. There are very little halachas involved in the mourning ritual and that just translates into the nature of the human being, that every one is an individual and their needs are different.
The time for mourning a child, a sibling and a parent is different and that too is natural. So watch your loved ones and don’t let things get too out of control or out of hand. If you think they are going too far, you might have to get them professional assistance.