The following is not legal advice. Not a lawyer, not your lawyer, etc, etc. Consult a licensed attorney practicing copyright law.
Personally, I'm not sure how enforceable that Privacy Agreement and EULA are. He might (or, more likely, might not) have something on the EULA, but he most certainly can't sue on copyright grounds per se. The law (as in the United State Codes) literally forbids him from doing so. Once someone purchase a legitimate copy of the copyrighted material, the First-Sale Doctrine applies, and the copyright holder can no longer prevent resale conducted by said someone (see 17 U.S.C. Section 109 and Bobbs-Merrill v. Strauss).
He could sue on breach of contract based on the EULA, but a cursory glance reveals that the sheet of paper containing the EULA (along with the Privacy Agreement online) are so poorly drafted as to make one wonder if there's any additional contractual agreement made
First, there is no definition of key terms such as licensor, licensee, rights granted, and actions forbidden. If none of these are specified, how is there a licensing agreement? It's like someone trying to lease a car but the dealer does not mention terms of the lease, the leasor, and the leasee. For comparison, look at what you agreed to before you are allowed to use MS Office. Big difference here.
Next, read the section under the heading "End User License Agreement" on the first piece of paper in the box. It does not prohibit resale of the purchased material (rather, it prohibits duplication, copying, and reproduction of the purchased material). Under the "Copyright" heading on the first piece of paper in the box, the Copyright Holder says selling of copyrighted material (as in "such material") is a violation of copyright law, but that argument is bogus (refer to First-Sale Doctrine mentioned above). If this were true, no one could ever sell used copyrighted books without first obtaining permission from the copyright holder.
Finally, let's examine the "Privacy Agreement." Specifically, first sentence of the first paragraph of the agreement reads: "The undersigned student of the PCAT Prep Class, Inc. agrees not to share, sell or distribute in any manner, materials from the class." Now ask yourself this, what is "the class”? Is "the class" 1) an actual class led by an instructor, 2) the Self-Study Course purchased, or 3) the entity “PCAT Prep Class, Inc.”? If the Copyright Holder doesn't define this, how would the end user know just what is forbidden? And if the Copyright Holder contends that it refers to a specific item, it would appear that “the class” refers to an actual class led by an instructor. Read the 5th sentence of the third paragraph of the Privacy Agreement, which talks about "said student" enrolling "in the class". In order for "said student" to be enrolled "in the class", "said student" would first need to pay additional fees, less what "said student" paid for the Self-Study Course. This implies that 1) "the student" does not become enrolled in the class by merely purchasing the Self-Study Course and that 2) the Self-Study Course is not material from the class. Thus, the provision in that first paragraph of Privacy Agreement does not seem to apply to someone who legitimately purchased the Self-Study Course from the Copyright Holder.
Now, what one may not do is to duplicate and then sell the duplicated copies. That would be strictly against copyright law, and the Copyright Holder can definitely sue for infringement (actually, he doesn't even have to spell this out, and violators will still be infringing). However, that's not the case here.
The site will be down briefly for a system upgrade Monday morning, December 11th, sometime between midnight and 5:00 AM Eastern.