Sisters Shania and Adriana Alamillo brought Shania's two-year-old son, Bryce, to a Tulare hospital in 2017.
He was in full cardiac arrest and had a fractured skull.
Bryce died two days later.
When Tulare Police searched their home, they found that Adriana's 3-year-old daughter was also being abused.
Police say text messages and videos uncovered extreme physical and psychological abuse and identified 45-year-old Edward Dias as the main aggressor.
The two women are already serving life sentences for their roles in the crimes.
Today, the Tulare County Superior Court sentenced Dias to life in prison without the possibility of parole.