What is the average survival rate of someone who has prostate cancer?

My father says that he has prostate cancer. But he keeps giving me two different statements. on one hand he said "oh I'll be fine, i plan on being here to see you get married, to know my grandchildren" etc. but at the same time he told me that he will live a few years more. I did some research on it and i got a page that says that the average survival rate is only five years. Though the page was last updated in 2006. I got a few more pages but they used words that I as a kid don't understand and got confused. Do any of you guys think you can help me? I'm worried and this topic is kinda taboo around my family, but I want to know. I want to know if I should expect him to die in five years or when I'm grown and married and have two little girls running circles around my feet!!! Please help me!