Best friend's brothers are insane and i don't know what to advise

My best friend is 19. His brothers are 29 and 32.

My best friend's Mom died two weeks ago and his two brothers took a spontaneous trip to London the day OF their mom's funeral. They booked their flight a few days after their mom died. Their dad and their younger brother (my best friend) were so upset with them.

I couldn't go to the funeral because I couldn't get off from work also my best friend lives on the opposite side of the US now so it was literally just the 4 of them at the funeral. The 3 brothers and the dad.

His two brothers went to the funeral bringing their LUGGAGE with them literally got out of a cab with their luggage at the funeral then left the funeral early. They stayed 10 minutes walked out and they took another cab from the funeral to go to the airport and have been in London a week now while their youngest brother (my friend) who is already on anti depressants for his depression and their dad who has a history of suicidal attempts were left alone all week.

My friend is so numb and can't comprehend how they could leave him and his dad alone at the funeral to go to London. His dad has attempted suicide now while they were in London and my friend text them about it and one brother wrote "He'll be fine" and the other wrote "What am I supposed to do? I'm in London I'm on holiday don't harsh my mellow".

I feel physically sick especially after seeing the screenshots of their texts. His brothers are insane they don't care their mother passed away and now my friend has to quit university because he has to watch his dad 24/7 it's so sickening. I don't even know what to do.