My days were pretty much like his, eat sleep, pee, sleep,shower, sleep.
My wife had to really ride me to get me to eat (via PEG tube) too. Truth was, I felt so crappy I really had nointerest in it.
He's at the point though, where he should start feeling a little better, and be willing to do more about getting better. Maybe give him another 2 weeks, but not much longer. You could ask the oncologist to talk to him at his next visit if thats soon enough.
Good luck, and Best wishes,
Mike.