"My grandma had her kids toilet trained at 1year old and so did my MIL (India)."
Now we know more about development and the importance of emotional wellbeing, eighteen months is the youngest recommended. Before that and it can be physically and emotionally damaging.
Many Old Women will talk about potty training. But it involved a child sitting on the potty for long periods and getting their legs smacked/shouted at, if they tried to get off.
I'm 50 and can remember a lit more kids weeing in the gutter and soiling themselves, than we would be happy with today.
Mine were done the Easter after their second Birthday. All Winter born, just so I didn't have the school run to do for my eldest. There were toilets everywhere, though.
My GD isn't quite ready at three, she has to take Movacol, though.
My opinion is that no-one includes when they were toilet trained on their CV, so as long as it isn't being done out of laziness of the Parent it doesn't matter.
I thought that the Family in the article needed SS involvement. He was a very disturbed child and they were allowing him to attack his baby Sister.