Manning sounds nutty, but the article you linked to doesn’t disprove what he alleges.
Boerner says they only roomed together one semester. The one bylined article wasn’t published until 1983. The Wiki link you posted speaks of him as having “few friends.”
Obama’s whereabouts from 1981 to 1983 remain very much in question.
Columbia must have had a 'special degree program' tailored for Obama because no one remembers him.