The bits I remember:
A man and woman (i think) are killed, leaving their baby son alive.
An ape- or maybe a chimp?- loses HER baby.
The chimp/ape takes the surviving human baby.
I remember some later bits, but not much:
The human grows up and finds his relatives.
One of them- an elderly gentleman- slides down the stairs on a tray, falls, and dies.
Can anyone help? Did I dream this?