Very classy gesture on behalf of the players.
I'm mixed in my feelings about the Clippers' response. Apparently, he had health care through his employment but decided to have the surgery done more quickly out of network. The Clippers position was "If we pay for him, we have to pay for everyone to go out of network, from the players to the janitors". I can understand why a business wouldn't want to do that, even if the humanitarian thing to do is to allow the guy to get the quicker surgery.
First let me say that Donald Sterling is a world class...well, fill in the blank. He is a terrible person, and is a plague on the NBA.
With that said, I cannot blame the Clippers for that decision. When it comes to doing things like that for your employees, it is just such a fine line. While Hughes may have been very deserving of it, there is always someone looking to cash in, and take advantage, and when a company does something like that for an employee, they set a precedent that puts them out there to be sued by any other employee who is not given the exact same treatment.
As a supervisor that works for a large corporation (that gets sued all the time by former employees), HR has pounded into my head how the most important thing when dealing with employees is consistency. The second you show favoritism to one employee, you are open to be sued. And particularly for a guy like Sterling who has been accused of being racist in the past, the pile of lawsuits would be a mile high after he decided to pay the medical bills of a white employee that are not covered by his insurance.
On the other side, good for the players. Its always nice when people step up like that. But this is one case, where I don't think we can blame Sterling (and really, we don't need this evidence to know how terrible a person he is anyways).