My best friend's brothers annoy me. is it normal?

He has two brothers. 6 months ago their Mom passed away suddenly no warning and his brothers went to Hawaii the week of the funeral. They booked it the day they found out their Mom died because they were already planning to go? They missed the funeral. Posted photos of themselves laughing and smiling in Hawaii while their Dad and brother (my best friend) were at the funeral mourning and depressed. I was at the funeral and saw how they posted laughing photos in Hawaii while we sat at the funeral home with everyone crying.

My friend told me his brothers seemed happy and unphased by the death. They even started singing the day she died as if they were celebrating her death.

Fast forward. My friend moved to another state for a one year work experience so had to leave his family home where his Dad was living alone after the Mom's death. He thought his brothers had been there to visit since he left 4 months ago when he got there to visit his Dad said he hadn't seen them in 4 months (note they live 10 minute drive away). He asked them why they lied about visiting Dad they had no reason.

He said someone needs to visit Dad while I'm on the opposite side of the US I'm only able to visit one more time in the next few months until my one year work experience is up. They refused to visit his Dad... Now he's thinking of quitting his work experience because his Dad is lonely and not taking care of himself since he's depressed because of the loss. All because his brothers won't check in at least once a month even though they live 10 mins away.

This annoys me. My friend waited forever for this work experience And he finally has it now he might have to quit because of his selfish brothers.