When we talk to Terry he mentions that Max gets his orders from El marrow (probably Hector). When we talk to Max he says El Marrow appreciates his help (or something like that). Then, we find a Double N ticket suitcase... and if we search in the prison of Rubacava (where Terry is in prison) we can see a poster offering a reward if someone finds a lost suitcase with the initials H.L. ... it looks like the suitcase Charlie steals doesn't it?
And it was in Max's "kingdom" :D he stole it? so Hector and him are not very good friends :D maybe a professional relationship with some resentment? :p that could explain why Max didn't kill Manny by order from Hector or something while Calavera was in Rubacava.
What do you think? are they friends, enemies... or both? :D

Nah, there friends alright it's just that Max was probably holding on to the briefcase because Max's intention were to get that out of Charlie's hands

And also about Manny getting killed, Hector didn't know that Manny was in Rubacava as it says in Savador's note (well not really) it says (but not quote) Manuel your name is spreading around in El Marrow, Hector's men are searching for you, I suggest that you travel carefully.

I always got the impression that they were business partners. I can't show any evidence to back this, but some of the things in Yohei's post make sense.