I think of it this way, some people can leave the house, get in a car accident and never return. You could never say what you wanted to say, you could never have closure. You have every opportunity to shower your son with love and try to prepare him for what might be the hardest thing he'll have to experience. I don't know you at all but I can tell the love you have for him. You will utilize this time, and you might find that you may share some of the best moments of your life with him. You keep fighting, and live every day to the fullest, and maybe... before you know it, another 20 years will have passed. Good luck mate, best wishes!