There is real question about Senator Tim Johnson (D-SD) recovering from brain surgery enough to return to the Senate. If he is incapacitated then a Republican governor will name a successor - most likely a Republican. That would put the Senate at a 50-50 tie with the Vice-President casting the tie-breaking vote. In other words, the Republicans would be in charge of the Senate.
This is great news for the Democrats. That means that the House can pass any number of symbolic bills, safe in the knowledge that it will never pass the Senate. They will have enough power to make a show but not enough to actually accomplish anything.
And they can blame it all on the Republicans.
On the other hand, the pressure will be off of the Republicans to clean up their act and get back to their roots, so it is bad for them.
The real winner will be the country for the next two years. With a split House/Senate, the Democrats will be prevented from doing much harm. Also, government spending night go down as the houses fail to agree on new spending measures. That is one of the reasons that Clinton had a surplus - the split between Congress and the White House.
So, as mean as it sounds, send Senator Johnson a get-worse card. Then send a card to the Republicans reminding them that they didn't earn the Senate.