Coping with death: callousness
On the frontier prairie, death was common. It's possible that it's going to happen in high amounts based upon a lack of retribution or law to have a community response to it happening. It's very possible that in a world without rule of law, that many deaths will occur and so people will grow callous to it, as long as it isn't happening to them.
Think about a nurse on an oncology ward. She sees death every day. She can choose to feel each one intensely, get close to only some, or try to distance herself from death to cope with the enormous amount of death that's occurring. Most people only experience a few deaths in their lifetimes in any close way. If you're almost daily or weekly experiencing death, you can become very brittle from that happening. A shaman in a post-collapse may feel the same way.
A whole generation may end up being very callous to death as a result. People might simply take the law into their own hands in vengeance, or they might create public executions, or attack whole tribes for the action of a single member. It may become a time of true lawlessness.
People imagine a death as a single event with one person dying. The death of a single family member in reality may dramatically change the survivability of their entire family. It will also change an entire tribe if it's a key person like a shaman or leader.
Because of retribution, sometimes families of an offender were also killed due to concern about vengeance. Sometimes captured victims who had been forced into sexual slavery (see previous posts about the Harpe brothers = river pirates) were also killed.
That way of coping is brutal, but historically possible based upon leadership and resolve.
I would encourage you to watch the Hatfield's and McCoy's special that was a three part series on the History channel. It took about 150 years for things to settle down.
[link to www.history.com
As you watch that, also realize they were very good friends to start who saved each other in wartime, but then the friendship soured. There were many times that peace was a possibility, but vengeance was foolishly chosen each time.