(((Mary)))
I'm so very sorry. That is terrible news, and it makes it harder when it happens during the holidays. Holidays just seem to magnify everything.
This will be my second Christmas without my dear DH. He didn't pass during the Christmas season, but he got sick the week before Christmas and passed the following February... so this time of year brings back tenfold, the memories of all those trying times. I can't stop replaying in my mind his last Christmas with us, how sick he was, and how we didn't even know it was his last Christmas at the time.
Cherish your time with your BIL. Nobody knows the future, so keep your spirits up and be as optimistic as you can. I am sending you and your family all my thoughts and prayers.