In flashbacks, a younger Locke is working at a toy store. A woman finds him and says that she is his biological mother. Locke gets a PI to check her out and he confirms that she is his mother. The PI gives him info on his father and he goes to visit. His father is happy to see him and takes him on hunting trips.
Locke catches his father hooked up to dialysis and offers to donate his kidney. When he wakes after the surgery, his dad is gone and wants nothing more to do with him. His mom explains that his dad made her do it and she went along with it because she needs his money.