There's an enormous amount of stress involved in a cancer diagnosis/treatment (been there); make sure you address this for you both. Some light exercise, funny movies, extra magnesium (Epsom salt baths are good); whatever you can.

Back when I had cancer, one of the worst things was feeling that I never got away from it. Some of it was by necessity because there is info to be gathered, decisions to be made, treatment, etc. but it was such a relief if someone could distract me with inconsequential chatter, make me laugh or just anything to get away from "IT".