What do I tell them?

Well today has been a horrible day. Besides the normal car breaking down stuff, we have just found out that Jack( John's dad) is not going to be around much longer. It kills me to even write this because I love them man. He has been with the kids almost every day since John has been home and they are not going to understand this, shit Neither does John. There ahs been alot going on with Jack the last 2-3 weeks and we all just attributed it to the Parkinsons, well it is not, it looks as though he has some form of aggressive leukemia, and only has weeks left. yes you heard me correctly. This is hard stuff. John and his Brothers have been at the hospital all day today, and have all been sobbing. Marla and I have been hanging out all night discussing how we are going to keep everything together. Frankly, I do not know what to do. Jack is completely aware of what is going on, and is very scared. So the boys are upset and scared too. See John's mother died suddelny with a history of depression etc, so her passing was not as hard to atke. But Jack is full of life and is always happy, life just isn't fair. YOu know what i am thinking, How do I tell the kids? they love him.... and I just do not know