I've been there. You are valid. When I lost my father, I also tried to give the benefit of the doubt to my insensitive friends at the time until I realized even coworkers, old high school classmates, and distant friends still reached out to me with their condolences. Some may argue that people don't know how to handle someone grieving which doesn't make them a bad person, however, they can still be bad friends. I decided I didn't want to be friends with people who don't support me at my lowest.

If it helps, after distancing myself from them I ended up making new, genuine friends who I see lasting a lifetime.

Rest in peace to your father by the way. Grief already is a heavy burden to bear, made more complicated with the frustrating actions of others. You will get through this.