I have found that most non-govt websites are incomplete or out of date. Yours is certainly the former, for instance; "some or all of the federal and state safety regulations may apply to your company" and "If your vehicle meets the criteria for a commercial motor vehicle, the following rules, regulations and laws may apply to the company, the vehicle and all drivers." May apply? How does that help? I could have provided that much. I guess you could use it as bullet points to search out which rules apply to your friend, which puts you right back at the FMCSA site.
Anyway, more than likely he could avoid all the complications by operating out of a step van type vehicle with a GVWR of 10,000 or less. One of the reasons I continue to work with my '97 is because the GVWR is only 10,500 so that allows me to pull trailers with GVWRs up to 15,500 and not need a CDL. If something were to happen to it I would get a 2500. That would give me a lower GVWR and allow me to pull trailers with higher GVWRs. With a '97 2500 I could legally pull trailers up to 17,200 GVWR. The point is, there are sometimes ways to get around the regs.