Hi,
I'm very sorry to hear about the quick recurrence and spread after your grandfather's surgery. The most important thing is for him to have peace and comfort. There must be aggressive treatment of pain, he shouldn't have to suffer from that. Most hospitals have something known as 'pain management', a team of experts. There are many different ways to treat pain these days.
I wish I could give more helpful or hopeful info but I'm afraid it sounds like the doctors don't feel your grandfather is fit enough for aggressive treatments like chemo or more surgery. Have any of the doctors mentioned hospice care? This is for when a person is not going to get more curative treatments but needs special care, leading to end-of-life care. It can be of tremendous help. Most times hospice workers come to the house (in the US). Rarely, it means someone can stay at a special care institution that focuses on their comfort, not cure.
Please have a look at WebCafe's pages on metastatic cancer and end of life issues, under this section:
blcwebcafe.org/metatcc.asp