Hi Allimsaying,
I am very sorry for your loss. Mourning is an extraordinary event and people react to it in odd ways, regardless their mental health, IMO. For example, when my sister passed away it was done a wake, as it is usual here in my country of origin. My mom is very old and fragile and went to sleep at home at night. My brother in law without warning my mom in advance, decided for my sister to be buried earlier. My brother happened to be in the wake and had to take a cab in a rush to get my mom to see my sister one more time before the coffin was closed. But when my brother came back with my mom to the wake the coffin was already closed and that was really traumatic for my mom. I do not know why my sister family did that (my intuition is that it was a kind of revenge against my mom, because my mom is a very cold person, but it is not something to punish, my mom is in that way due to traumas during her infancy). I was not in my country when my sister passed away. I called my nephew and nieces and eventually asked for an explanation, but they could not give anyone.
The aunt of a friend of mine passed away before my sister did. Her father (he is the brother of the deceased person) was in a cruise when the person died. The family of the deceased woman told the father of my friend about the death. He said them to hold on that he was trying to get a flight to attend her sister burial. They said yes, but then decided burry her without waiting for her brother. So the man abandoned his vacation for nothing, when he came back the sister have been already buried. Perhaps, in this case it was also an unconscious revenge against this uncle that had taken vacations regardless his sister was gravely sick. But I think it is not OK to change plans once you told somebody you will wait for him to come back to be able to participate in the funeral.
Anyway, I am not sure these examples will give you some relief, but it helped me to know the story of the father of my friend when I learned what the family of my sister did.
Hope you feel better soon.