Teenager Jonty Bravery is serving a 15-year sentence for the attempted murder of the seven-year-old child.
His parents said their "little knight" was able to enjoy his first holidays since the incident and build sandcastles by the sea.
Bravery was a 'looked-after child' under the care of Hammersmith and Fulham council at the time of his murder attempt.
Bravery, 18, admitted attempted murder after throwing the six-year-old boy from the 10th floor.
The 18-year-old will be sentenced this month after admitting throwing a six-year-old boy from the 10th floor of London’s Tate Modern art gallery.
The six-year-old suffered a bleed on the brain and fractures to his spine, legs and arms.
"We can now bring him outside in a wheelchair to breath fresh air. It’s tiring for him but he really likes it, of course."
I'll never forget dragging my daughter away kicking and screaming because she "wanted to touch the paintings".
The six-year-old boy is in a "full armour" of splints, an update from the family said.
Jonty Bravery is accused of attempted murder.