Sounds like a major lack of leadership - the kind of thing that happens in a college project.
This kind of behavior, to me, speaks to me of dysfunctional management and I think it's probably good in the long term to get out of that kind of situation.
Lesson to be learned: You can't ignore others on the team. You can't have clear separation of duties without strong management or a good working trust relationship. Both of these are weakened if you're remote most or all of the time and the culture doesn't reward/support remote workers.
People just sort of assumed that he had been appointed project manager after that.