There isn’t any dispute. Your friend broke the rules and is banned. Ebay can be very understanding, as when I was scammed a couple years ago. They saw my long good history there and gave me the benefit of the doubt, I explained my innocence at being scammed and all was well thereafter. I think they “limited” me to only earning $2000 a month there for X number of months. I never earned that much so it didn’t matter.
There are sites where you can change your IP address but why would this guy want to fool ebay?
A very high official with ebay called my friend today and explained that the situation had reached the highest levels of ebay. He made it clear that such postings are intolerable, but due to my friend's professional demeanor on the phone when discussing the issue with ebay and especially the problem of not getting a warning, the account would be reinstated should the postings not be repeated. The man was very professional and nice to my friend. Pretty wow. Account will stay clean, friend said, and life goes on. Interesting your take on being banned. The comments must have upset you too. Why are you here?