I've lost it to quote it now but the post a few minutes or so ago from a mother with an autistic daughter is really enlightening so thank you for sharing that.
family members (who never bothered to see him or help MIL as they ‘lived too far away’ and who managed to travel though to the funeral and stuff their faces afterwards as they told us they even managed to take food for the journey home then the next sentence calling us out for behaviour).
I have been, and in some ways still am, a carer to family members, I understand the strain and toll it takes on a person. I've been the person frustrated with the sibling who doesn't seem to bother.
I've also been the family member furthest away who cannot do the practical support and aware of the resentment building from the relative who is close enough to do it.
Much of the time, people do what they can. Often if they're not stepping up it's because they don't realise it's needed or because they can't find a way to do so. It doesn't mean they don't care.
I'm also ND, although I don't (clearly) share your feelings about funerals. They can be hard, yes, and confronting. But at the same time they're also cathartic and comforting.
People are often at a loss of how to approach each other when there's been a bereavement, how to offer help & support. Funerals give people a place to do so and contact with the bereaved so that they can offer support both emotional and practical.
For many people, funerals are a way to channel and manage their intense emotions when bereaved.
One reason why people eat a lot at funerals is because they need to. Grief is exhausting, they need the fuel and the comfort which food can bring. Mourners also may not have eaten beforehand because of emotions they feel. It isn't greed, it's coping.
I don't say this to attempt to change your beliefs, but to help you have compassion for those who didn't clean the house or do the appointments. Their grief and need is as valid as yours.
The undercurrents of resentment I pick up in your original post are normal, but recognising that other family members are in pain too will help you manage this situation and avoid family fall outs.
It's also worth considering that you SIL may be struggling with the fact that you got to spend so much time with her father. The rights and wrongs of that are largely irrelevant and for a different thread, but suffice to say compassion is what is needed now.
When compassion is given, its easier to return.