The news from the North had been very unreliable. The spy that he had planted in Winter town long ago was killed when Ramsay Snow sacked Winterfell. Ever since, he had to rely on rumours coming from White Harbour and Barrowtown, both of which were quite far away from Winterfell. The only reason that they knew Stannis was dead in the first place was because Roose Bolton had sent a missive of his victory. However, they had gotten only silence ever since, boding badly for House Bolton.