You say your husband was recently diagnosed. If you're anything like us, then this is an incredibly stressful time for you. When my husband was first diagnosed we went through a whole gamut of emotions each and every day...mostly just total shock and devastation. Your dog could just be picking up on the tension and stress. Animals do react differently.
We had a miniature schnauzer, and the dog seemed more tense when my husband was first diagnosed. We attributed this to Dave's illness but later found out that our dog was quite ill at that time. Believe it or not, the dog had cancer, too. I lost my little dog only a few months after finding out Dave had stage IV cancer, and that was a double whammy for me as this little dog was my best buddy! You might want to have your dog checked to make sure nothing is physically wrong (it's a longshot but still might be worth checking into).
Our cat, however, who had never shown much interest in Dave, was suddenly his best friend. All I know is that animals are incredibly sensitive. My best guess is that the dog is picking up on all the stress and tension and just reacting negatively to it. ??
Nancy