I know this is stating the obvious, but working at a clinic and interacting somewhat regularly with cancer patients, it's pretty invaluable for their friends and family to just be there for them. Goes for the families too, in general. I think you're doing a great thing.
Not all that long before we were married, Mrs. DeTiger lost her mom to cancer. We spent the week with her that she passed as we knew she didn't have long. She really appreciated it, and my now in-laws did too. Sounds cliche, but there's a lot to be said for just being there.