Story updated:
Two-year-old twins were killed when a chest of drawers fell on them while they were playing.
William John and Betsy Louise Woodbridge, who only turned two last month, were trying to climb on the drawers when the accident happened.
Their parents, Paul, 37, and Louise, 33, are being comforted at their home in Winkfield, Berkshire.
A private funeral for the children is to take place on 5 October at St Mary's Church in Winkfield.
The toddlers were having a nap in their bedroom while their mother was downstairs with relatives, including their grandmother Frances, when the accident happened some time after 1400 BST on Monday.
The family is just shattered out of all existence
Ruth Roll, family friend
The twins were taken to Wexham Park Hospital in Slough - one by air ambulance and the other by land ambulance - but were pronounced dead on arrival.
It is believed the youngsters may have pulled the drawers out of the chest and used them as steps to get to the top.
They leave a 10-year-old brother, Ben, and a four-year-old sister, Lily.
Their mother is a director of Grundon Waste Management, owned by her father Norman Grundon, who appears on the Sunday Times Rich List with wealth estimated at £44m.
The twins' father, who was out at the time of the accident, is an executive with the company.
Ruth Roll, a family friend, said: "They are a very close family, the community in which they live is very close and everybody is completely devastated.
"The family is just shattered out of all existence."
An inquest into the incident, which happened on Monday afternoon, was opened and adjourned, and will be reopened at a date to be confirmed.
A Thames Valley Police spokesman said after initial inquiries the deaths were not being treated as suspicious.