The only way I know what information university officials were looking at when they made their decision is because of HarvestMoon’s post and link. If the only information available to me was media reports like in the OP, I would think he had been treated unjustly.
If the friends who reported the violence had called the police, I guess there would have been a report and the information would be more publicly available. Would he have faced criminal charges? I am comparing this to the Brock Turner case. If no police had been called in that case, and it had only been reported to the university, what narrative would we have had?
With regard to witnesses being available for the appeal, that seems to me what happened when Paul Nungesser’s appeal was successful. The accuser had graduated and stated she didn’t feel she could take off work to appear for the hearing. She had already been through the process, which was “initially decided against Nungesser, with an assigned punishment of disciplinary probation”. (copied from wikipedia) His appeal was successful because she didn’t show up, if I understand correctly.