1) it’s not entirely revealed but hinted in a subtle way. It’s mostly in chapters 36 (What Jad did to White) and 37 (How Jad’s actions affected Black’s world) where the hints are.

2) White lived entirely with his mother til she did what she did. (talked about in ch39). She was present, in one way/form or another, in the first 8 years of his life (Up until he met Black).
Almost nothing is revealed about her relationship with Jad other than she wanting Jad more than wanting White basically. 

Have fun writing! I can’t wait 😀