I remember when KK identified as Indian, she was brought up by her mother. I assume that was why or maybe her Fathers Slave dealing History?
She also has a bit of a history prosecuting Black Americans.
I am going to assume you filed for them as immediate relatives so there are no derivatives.
So yes assuming the other Parent is agreeable a new LPR can petition their unmarried child, going to take a while.
Not sure where you get those numbers from, more like optimistically 15 and 25 years.
We still do not know if he has a chance to visit, and visiting does not include being a home health carer.