Student should go ahead and publish
I don't see anything wrong with the student going ahead, publish and obtain his advanced degree. Since, as B recognizes, he has not yet qualified as an author, and since B has not responded in a timely way, the student is justified in going ahead and publishing. Of course, he student should fully acknowledge all of B's contributions in the acknowledgements to paper.
An Uncommunicative Research Supervisor posted by andrew
Supervisors are often remiss in giving timely responses to their students posted by CarolineWhitbeck
What has the other supervisor, A, done? posted by Helpline Advisor 1
Student should go ahead and publish posted by Helpline Adviser 2
Research Supervision posted by rholland