Sandi,
I was diagnosed with NSCLC in 2004, and told I would be lucky to survive one year. I began taking AHCC the second week after my diagnosis. I just made my three year mark in March. I believe the AHCC had a huge impact on my strength and endurance, and also enabled me to gain weight as well. I had six months of chemotherapy, along with 52 radiation treatments to the chest and neck. Quite intense therapy, yet I was able to drive myself to all 52 radiation treatments and also continued working throughout the treatment (only missing some days when the chemotherapy effects were at their worst). I am still taking AHCC, and will continue taking it for as long as the Lord keeps me here. I'm not a doctor, but I think AHCC would probably help your Dad alot. I order mine from the internet, and there are many places who have it. I buy "Source Naturals" brand, but there are many to choose from.
My only other suggestion... prayer. I am here through the grace of God.