I admit the scope of the project is overwhelming, and I've told my client that he's asking for an NSA quality project. I will direct him to this post and your replies to help him to better understand the nature of his requests. Also, it appears that my article was truncated before being posted, so some of the explanatory bits were cut off, although the core of the question is still there for the most part.
And yes, this is an actual client, not myself. I already suspected what most of you were saying, and tried to tell him that, but computers are a big 'mystery box' to him, and I can't seem to nail stuff home on my own. (IF it was myself i would have all already solved this problem.)
Also, I'm a little surprised at some of the hostility and non-seriousness i've seen here, but I suppose it is to be expected considering alot of the drama and arguing i've seen going on in other arguments. When I originally wrote the article, I did specify 'serious answers only please, I don't want to start an argument, but a bunch of random answers that are unrelated won't help me solve this problem'
And to be more specific, it's a home network with a cable connection. (I obviously can't be too specific due to his need for anonymity to avoid 'alarming' his family to his clandestine monitoring intentions). He does reasonable cause for suspecting something is going on and just needs to have information available to aid him in making decisions about some unusual behavior. and yes, I know that you can't get 'screenshots' right off a client PC through a network, by screenshots i meant some kind of recreation of a visited website, or just text information in printable form off some kind of analyzer software.
I really would like to solve this problem, but I agree it's an excessive project. He wants the moon without having to go there to get it, type of issue.