I am sceptical about the 147 minutes, the child could have still clinging onto the ice and just drowned a minute before the parents reached the pond.
It seems below about ~80F you lose consciousness. This kid was nearly half that. Moreover, there have been other similar cases: https://pubmed.ncbi.nlm.nih.gov/32482520/
Ice-cold water won't let you have enough strength to cling to ice for two hours. Ten to fifteen minutes at most.
Survivors of Titanic would say that the shouts of people clinging to something in the water died off pretty fast.
The timeline lists "Sled tracks seen to broken bond ice, EMS called" at 16:44. He was pulled from the water at 18:57. The article text further clarifies:
Parents discovered sled tracks from home onto broken pond ice through which he fell.
He left the house at 16:00, which is why they give the range of 147 to 177 minutes.