Mrs Maddren said the man, who may have been intellectually disabled, and his caregiver had gotten into a heated discussion before the incident occurred.
'The next thing I knew he had turned around, I think in frustration or maybe being little bit overwhelmed in the situation he was in, and just lashed out,' she said.
'It was quite a thump. He didn't even cry but he was confused about what had happened. Everyone was quite shocked.'
'I understand him trying to get him out but if he just said I hope you're okay before he left it would have been understandable.'
When Theo started vomiting later that afternoon, he was taken to hospital and closely monitored.
Thankfully doctors believed the vomiting was the result of a virus, and not a concussion. He was then given the all-clear to return home.
Theo's father, Shane Maddren, said his little boy has now returned to normal and his concern is now focused on the man who attacked their son.
'We just really want to make sure that he's got support for him, because I'm sure his carer will be feeling awful about what happened,' he said.
Police have confirmed they are investigating the incident.
This article originally appeared on That's Life!
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