Of course ... A sick man can be a philanthropist!
Of course, just because clif (and I) hear modern American English speakers respond to "How are you?" with "I'm good." does not make the phrase proper, in the sense of traditional grammar. There is a reason why "well" and "good" are two different words -- they help us distinguish what one means when he speaks.
If I ask a rowdy young man: "How are you today?" And he responds "I'm good," I should be able to assume that he means "I'm not going to be bad and act off today." Rather, he will be a good boy, well-behaved.
If the fellow says "I'm well," I should take it as suggesting he is not ill.
If the same fellow "feels good", he may be open to doing some community service. Or, his girlfriend recently told him she likes to touch him. He "feels good" to her.
If the fellow says he "feels well", he should mean he is not ill, or that his own hands work well at distinguishing textures and such. He "feels well" as opposed to one whose hands are more or less numb and who cannot fell at all.
Lazy language speakers should not, alas, determine for the rest of us what is proper and what is simply misleading or wrong. Unfortunately, when we have a living language we must accept that the language will change. Still, some things should not change precisely because they allow us to comprehend with some sense of precision -- which is one of the functions of language to begin with. "Good" and "well" basically provide such precision.
I hope that's all well and good for you.
--SONNET CLV--
Note -- "A sick man can be a philanthropist" means that one need not be well in order to be good.
"How are you, Mr. Philanthropist?"
"I'm good ... but not well."
"Well, that's good, and not good as well."
"Still, I'm good ... at what I do -- which is giving away money."
"You certainly do that well."
"I only wish I were well."
"But at least you're still good."
"True. I'm good at being good, and not so good at being well."
"Well, I wish you were as well as you are good. Tell me, if you had your druthers, would you prefer being well or good?
"Good."
"That's spoken well, which is why you are so good."