If he does work hard to elect House Democrats, it will be a change from 2010 and 2012, when he didn't do much at all for them.
But let's say he does. What are the chances of success?
Certainly not zero. Democrats need to gain 17 seats to win a House majority of 218. That's fewer than the number of seats that changed party in 2006, 2008 and 2010.