How to help without helping too much?

I’m trying to figure out how much help to offer without overextending the helping hand. My dad is back from the hospital, but still feeling fairly weak. I want to help him as much as I can, but I know having a sense of purpose is important to the human spirit in recovering from illness. I’ll grant that his chances of recovering from leukemia are unlikely, but I don’t want him to give up either.

He’s always been self reliant and only asks for help after trying a thing from every angle by himself. So how can I help him with household chores and errands while leaving him that sense of independence and self control that I know is so important to him?

I just don’t want him to have any sense of being a burden, but at the same time I know he gets winded just walking to the bathroom.