Death how do they forget about it so soon

My brother died 11 years ago in a terrible farming accident. I saw it all happen and remember holding him in my arms when he died. I knew he was going to die but I just didn't want him to. He wasn't supposed to die so young. To this day I sometimes cry myself to sleep. I don't talk about him because it hurts so bad. I didn't grieve in public or around people after the funeral but anytime I was by myself I cried. I blamed myself for what happened. I was angry at god for taking him instead of me. I wished I was dead. Probably the only reason I didn't commit suicide was because I didn't want to cause my family further pain and heartache. I had a really hard time especially since my brother was only about a year younger than me. We were very close. I tried to figure out how I could have prevented his death but there was no way. Because of his death I have become a very numb person. I don't feel anything when I go to other peoples funerals anymore. There isn't a lot that can hurt me anymore. Some people don't grieve or cry in public but that still doesn't mean they don't behind closed doors.

Just because they go back to their normal lives doesn't mean that they have forgotten about the person who dies. Most people just try to put that person in the back of their mind so that it is not a weight on them. Take me for instance a year and a half ago my grandmother died of cancer, and she was like a second mother to me. When she was diagnosed it was horrible for me but then she went into remission only for the cancer to come back. It was originally lung, then it spread to the pancreas, and the liver, and from there everywhere else. She had lived a tough life and was the strongest person I had ever met, but I watched for a year as she lost her hair, and her skin turned yellow, and she was confined to her bed. Eventually she slipped into a coma, and awakened only to be able to not speak or barely open her eyes. We knew she was gonna go, but I didn't want to say goodbye because I wanted to remember her the way I knew her throughout my life not like that. Eventually my family convinced me that to give her closure I had to see her. So I went to her home and as I walked in and said hi she struggled to hold open both eyes. I talked to her for an hour and when I left I broke down in tears. That night she died. A week later we had the funeral, and honestly even though my family talks about her every time we're together I never do, but it's not because I don't remember her. The truth is not a day goes by where I don't think about her, I just stay silent, and continue to live my life normally. In truth I think this is what everyone should do because why stop your life after a person has died, you shouldn't, you should continue to live your life and enjoy it even more because that person who is gone can not.
So don't worry you won't be forgotten when you're gone.

Most of those people weren't directly related or connected to the person who died, so, naturally, the grieving process is going to be quicker.

Also, why keep talking about a person who has died? It's only natural to forget and start caring more about those who are still alive. Don't be mad at them for moving on, they obviously didn't have a super strong connection to the people who died.

Grieving for a while is okay, but you can't keep living backwards and remembering and telling old stories about someone forever, eventually you have to make new memories.

It's not that they "forget" about the person. That person will always have a place in their life, and their thoughts.
Maybe some just don't see the point of sticking around and crying another minute. Because really, not to be offensive or rude here, but what is the point of crying another tear? It's not going to bring that person back to life. That person who is gone now won't feel or even know the sadness everyone is feeling.
We all come to a point where we lose something, and all we can do is take a deep breath, and move on. For some people it is easy, and for some it is hard.
But just because it was easy for some to move on, doesn't mean the thought, and memories are erased as well.

I lost both of my grandfathers when I was in high school--one in 2004, one in 2006. I don't talk about them all the time or cry over them, but I think about them every single day. I still miss them, and I wish they were still here, but I don't dwell on it. No one in my family does. It's not good for people to mourn a death for a long time. But that doesn't mean the person is forgotten.