spend all the time you can with your husband, take pictures, videos, etc, and have him, if he's able, write down anything and everything he wants to leave for family/ friends (words of advice, etc). It's hard, i wish we'd done that with my Dad and i did take lots of pictures, but never recorded anything, and i wish so much i had. When we found out about his brain tumor, on my birthday in 2011 (October 4), we didn't have a lot of time, but the time we had, we made sure it was good for him...and all of us. He passed 4 months later.
you'll both remain in my prayers, and stay positive, to keep him that way, too. Hugs to you both.