“I really need some data from CW to get my stuff done, but (s)he’s taking a really long time; (s)he may need some help. I don’t have the time to work up that data and get all my own stuff done, though. What do you suggest?”

I fear that, if you don’t speak up, your bosses might get miffed at you for “covering up for CW” or “allowing incompetence to run rampant in the company” or “not getting your job done regardless”. Bosses think all manner of strange things.

Just try to phrase things as politely as possible.

That or get them transferred to a miserable and far-away-from-you job.