In a collapse, everything that you count upon for support will be taken from you. As these things become less and less prevalent, many people will die from a host of issues with medication, pre-existing health issues, mental strain, malnutrition, dehydration, injuries, accidents, suicide, murder, violence, etc. The grief will ramp up over time, and you'll have less and less family and friends to count upon. Many will have no one that they love or care for still alive.
Today people mostly concentrate upon things to distract them. If that doesn't work, they distract themselves by living vicariously through entertainers' lives. They actually ignore their family and friends and don't see them as the vital resource that maintains their sanity and balance. Ultimately people today are extreme narcissists only focused upon their own needs.
Many people have forgotten spirituality altogether. They feel that they are along in the Universe, and that the Source is a myth. They immediately discount all of the world's religions as nonsense.
Some however feel that while it is improbable, it makes life more precious. It means that there is only this life and so each moment should be lived into with fullness. I do respect this idea, but I don't agree at all that this is the only life. I can find resonance with them however, and creating community with people you don't agree with is a valuable skill.
We will daily be consumed in a grinding task of mere survival, if unprepared and not possesing skills, supplies, and seed. We will turn over and over every loss and every death, and it may drive us either to very negative reactions or even insanity. Some will become violent and vengeful and that way ultimately leads to death too.
I think for me, the only way to cope is by being positive. I may not have any happiness at all, but I may be able to help someone else find flickering moments of joy in a meal, in growing things, in kindness, in listening, in healing, in teaching, in hugging, in tenderness, and in holding their hands in the darkness to come.
Real faith is not about the afterlife. It's about living in and creating the Kingdom of Heaven here and now. The only last bastion against evil and death is the human heart.
In the end, the only way to withstand crushing grief is having friends, family, and God to sustain you. You, alone in your thoughts of crushing grief, will not be able to continue living by yourself.
He must increase, but I must decrease. John 3:30