Diana’s sons were required to inspect the plans for her grave. They were eleven and fourteen years old. The decisions about where their mother would be buried were made by adults. The boys were shown the plans and asked if they approved.

After Diana’s death, the question of her burial became a matter requiring decisions by her estate, her family, and — by the particular logic of a situation involving the mother of two royal princes — a degree of consultation with the palace.
Earl Spencer proposed burial at Althorp, on the family estate, on the island at the centre of the ornamental lake. The decision was his to make. He made it.
William and Harry were, by the accounts of those close to them in those days, involved to the extent that they were shown the plans and asked if they had any concerns. They were eleven and fourteen years old. They had lost their mother five days earlier. They were being asked to approve an architectural decision about her burial location.
What they said in response to being shown those plans is not documented in detail. What is documented is the outcome: they approved the arrangements, the burial proceeded at Althorp, and the island has been Diana’s resting place for nearly thirty years.
Harry has written about those days at Balmoral and in London with the quality of someone who is still, decades later, working through what it meant to be twelve years old in that particular week. The burial plans are not a specific subject he has addressed.
He was twelve. He was shown a drawing of an island. He said yes, or something that was taken as yes. She was buried there