I was reading something on Rockstar North's website, and in links section was "West Coast Rap Legends". I went to that link, and I remembered that I saw it before, but I didn't read the text. I read it, and while reading about Madd Dogg, I saw this:
"But like all genii, or whatever the plural of genius is, he was troubled. He suffered personal tragedy when his manager was killed (just proving that the streets will get you in the end, for real) and he kept losing his rhyme book and his mind to drinks and drugs."
Remember how on the end of the game CJ becomes Madd Doggs manager.
Maybe it is old manager, but sounds interesting