I concede to your superior argument. There is a better way to look at this topic but I still don't like the crippling debt cancer treatment leaves with families. Though stealing is a strong word, I'd use copying.
This is incorrect. And you're making the same mistake as the one you point out in your next sentence. Using an euphemism to simplify a complex ethical question (possibly incorrectly).
According to this [1] theft involves a component of denying another person with rightful possession of that property its use. When dealing with ideas (and software, algorithms, math etc., etc.) we're dealing with new ethical questions that we shouldn't hurry up and sweep under the carpet by pigeonholing into our previously inadequate understanding of ethics. Doubly so when it deals with life and death as in the case of drug patents.