I am so very sorry you are going through this. Fear is a normal response in this situation. For me , my faith is what helped me to deal with cancer and fear the most.
Do you have a faith foundation you can lean on? You said this was his second time? What helped you thru the first experience?
Sometimes having someone to talk to is helpful. A pastor, or therapist, even a trusted friend . Most hospitals have a Chaplain service that can offer some specialized supports or referrals to support groups etc. Chaplains are familiar with supporting individuals in crisis. I know this is a time of crisis for you.
You will also get lots of support and input from this group.
In my thoughts and prayers Chaplain Lynne