Nephew ofa adult toddle

My uncle is a toddler and is active on this site. 
He decided to stay a baby of 15 months old after he was given a ultimatum 

my father was Unfortunately  not a  good person and treated him badly 

he stopped us seeing him for a long time and tried the same with all the family  by telling everyone about his

Brother that spends all the time as a baby and never used a toilet he just dose everything in a nappy 

even when his mother had a accident he was still trying to  alienate Colin

so after a long Conversation Conversation with some family members we decided  if the opportunity arises 

we would just treat him like a baby