I think it's fairly simple. Garry and Brian are doing negotiations with a player's agent, in this case Dr Onuoha. She's trying to get a better deal for her client, in this case her son. In an attempt to extract higher wages she cries that she has cancer. In reposnse, Garry writes to his co-negotiator Brian, director of football, and says
"Ravaged with it!! ... I don't know how you sleep at night. You used to be such a nice man when I worked with you at Nike. G."
Meaning: She has cancer and here we are not giving her son millions a week, how do you sleep at night knowing life for these obviously poor people is so harsh! Considering we haven't folded and given them their millions, we must be considered bad men and gosh darn it, you used to be such a nice man at Nike!
Does that make sense now?