Was coughing because Mace fucked him up at the end of the Clone Wars. As he was escaping with Palpatine, Mace came up and knocked him back with the force and crushed his chest plate. He was a cyborg, so he had human parts. That's why he was coughing so much. There were a lot of subtle Clone Wars references in the movie.
Nobody mentioned Sam Jack's "not going out like a punk" (his words) death?
I gotta absorb this one. I'm sure I'll be one of 2 million posts tomorrow evening after I watch it two or three more times.

"...most sistahs only recognize a good
man when he's a character in a shitty
movie, a shitty play, their favorite
daytime soap or a shitty book written
by a homosexual."
From Reggie Eggert's online review of
"Diary of a Mad Black Woman"

"Ern