I suspect an author of a paper I'm reading was listed improperly - what to do?
Can? Yes - the comments already give you some hints: Look at the prof's website, try asking him a question about the paper.

Should? Probably not. If there is really something going on, then it would the business of the professor, not yours. If you proceed as above and ask him something, and there is really something fishy, he can decide by himself if something needs to be done.