LindseyMai, my heart goes out to you for the isolation & loneliness that our journey entails. Losing friendships and being disappointed with some of the closest friends has been the most surprising thing in this journey. I love the stage 1 and stage 4 analogy given above. My view is that I had three circles of friends: circle 1 was the closest and most intimate friendships; circle 2 was that of friends who are more distant or whom I see less frequently; and circle 3 was the acquaintances. I decided that I want to save my energy for my terminally ill husband and me. So I shrunk the circles from 3 to 1, and shrunk circle 1 to those who have been there for us. It is amazing how many strangers and new people have come into our lives. So for every friendship we have lost, another one has sprung up. I was very upset and angry the first year or two. And whenever I spoke to others about it, it would make me even more angry if they tried to "explain" it away. But for all the reasons given above, and hopefully with time, you will realize that some of the people you are letting go of are not meant to be around you. What has really, really helped me enormously is that I have two acquaintances-turned-friends with whom I meet once a week. It started as a group for eating disorder support, but we now talk about EVERYTHING. Every emotion I go through, all the difficulties and the challenges, related or unrelated to cancer, grieving or eating disorders, we discuss. I find from them unconditional love. It has helped enormously, especially since, as you mentioned, you don't always want to talk to your mom about cancer, knowing that she has wounds of her own.
With my husband's family (he has brothers who don't ask much about him even though they live a few minutes away), I concluded that they are too scared to see him vulnerable, and as others have noted, his condition reminds them of their mortality. It used to anger me a lot. I now realize it is their loss, and that we each have our own journey. I also found that when I myself accepted uncertainty and the ups and downs of terminal illness, I was less angry. I can't change others, but I can change how I am with my husband's brain cancer.
You have come to the right place for support. We are here for you. I give you a virtual hug and send you lots of warmth from Jordan. Hang in there. One day at a time.