Poor baby. I feel so very sorry for the dad. Mom could easily have sent him back, or just refused to have him visit in the first place.
One of the worst experiences of my life was being on a jury in a child abuse trial. Mom's boyfriend darned near killed a kid. There was every indication Mom knew things were going on, but she was proven not there at the time.
I'd rather sit on a murder trial jury any old time than another child abuse case. (Not everybody has the same harda** view of things I do).
I'll also never understand how defense attorneys sleep at night nor look at themselves in the mirror.
Because the main intent was to inflict suffering on the biological father? I have read a (mercifully VERY few) True Crime accounts of two legged things who killed their own children in order to get revenge on the other parent/spouse. (We know that was their motive because they left a note (sometimes a suicide note, because they killed themselves afterward) or told the investigating officers that's why they did what they did :
Ronald L. Shanabarger remains the most egregious example of this vile perversity of which I'm aware-and thankfully such crimes are rare, though of course only one case is one too many.:-(