I don't think we have a clear picture of what was going on with King and about who was taking care of him. I don't think it's very possible for King to have been just sent to the stepfather all the time. His uncle, which is the brother of King's mother has a tonnnnnnnnn of pictures and videos with him and they all seem pretty recent. It appears this uncle and the mom live in the same house, so it kind of looks like King was in his mother's care quite frequently.
We are just assuming this "babysitter" has been caring for him for two straight years but observing everything closely, it's most likely not true. I don't doubt she has been babysitting him for 2 years, but for 2 years straight? No.