Hi Teresa Rice,
We have a health forum listed under Cancer, there you will find people discussing several forms of it to include prostate. If you like you can go there and read some of the posts, just to give you some peace of mind and a little more support.
The green stuff that is coming up is more infection due to the cancer. He needs to keep his head elevated at all times so as not to choke. What you can do is what you are doing now, continue to be by his side and love him. Keep him as comfortable as possible, live each day to the fullest and if he doesn't know the Lord, please introduce him to him. Read the bible to him and if he hasn't been baptized please allow him to be. If neither of you are Christians, this would be an ideal time to beome one. I will say a prayer for you.
God Bless,
Faded Rose