I'm pretty sure he's not dead, unless both Wikipedia and IMDB are wrong.

His wiki doesn't mention that French died.  The rumor is that they killed of Bill from the original L4D team because French didn't want to reprise the role.  I've heard nothing about the actor having die and people are usually very quick on the updates of a wiki page when news of death of a actor.

broken telephone! *ching*
 
breen's voice actor died. bill the character died (or at least that's implied, apparently they just say they lost him which usually means bit the dust unless they just lost him, which would truly be hilarious. they could make the next DLC is senile ol' bill takin on zombies with a new crew in hollywood)

They killed Bill off because Bill's voice actor was busy when they needed him to record for the character. That's it.

I thought he was in jail.

In other words, it's all speculation. 
 
 
I heard the voice actor relocated and didn't want to reprise his role. I doubt he's dead, but who knows?

Destructoid ran an article back in Jan 09' about Jim French getting shot by cops. After robbing a convenience store (for ammo and first aid kits?) then waving a gun around he gets shot to death by scaredy police officers who most likely thought he was about to become a zombie.
 
No mention if he respawned in a closet or bathroom.

" Destructoid ran an article back in Jan 09' about Jim French getting shot by cops. After robbing a convenience store (for ammo and first aid kits?) then waving a gun around he gets shot to death by scaredy police officers who most likely thought he was about to become a zombie.  No mention if he respawned in a closet or bathroom. "

I guess Jim French is just destined to become a urban legend in the gaming community.