When our son died very unexpectedly, all my DH and I wanted was to hide away. We had not a clue what he would have wanted - certainly no fuss. But DD, as a vicar, told us it was imperative to have a funeral, with coffin for his mates to see and be able to properly say goodbye.
There were three short talks, one from his brother, one from his best friend and one from his work colleagues. There were three coffin was cardboard as he had been working in a pape4 recycling factory. The church was full.
When DH died, he had chosen the music and the vicar to perform the ceremony. A surprising number of people attended.
It is cathartic for the family to have some sort of send off, also to have some sort of idea what the deceased wanted.