I am sorry to hear about your fiance' also. I am also sorry for what you are now going through and will go through in the future. I am not a dr. I was diagnosed with stage IV Laryngial cancer four years ago.I have had three surgeries I have had four sets of chemo and I'm starting my fourth round of radiation. I have some metastisis but it has been checked by the chemo/radiation.
There is always hope. When there is love, all things are possible. Stay with him to keep him strong. Help him make decisions but respect that the decion is his, know that he is going to get sick-- angry-- tired-- and have HUGE mood/attitude changes. Just remember who he was before and what you love about him. He can make it through and learn to manage and will be able to return to some resemblance of 'normal'
I cannot tell you how he will react or what will happen becasue everyone is different. I lost my wife to cancer two months before I was diagnosed. She was always positive, always up beat, a real jewel. I am not like that-- but my kids have learned to cope.
He will have a difficult time but you can make it a sweet time, one full of great rememberances when he comes out on the other side of this horrible desease. To answer your question... Is is curable? everyone is different and everyone responds differently so there is hope. If you get an answer you don't like-- ask again-- or ask another doctor.
Be careful of finances. Don't charge anything on credit cards (they show up negatively on you credit report). Use your insurance when you can and ask the dr. office to let you pay out the rest, It will undoubtably put you in a financial hole, but sit down with someone you trust (that is a little further from the situation than you are) and ask them to advise you.
Good luck--
Travisdean