He could have learned mirrored writing. Would have allowed using the board in in-person lectures. Not that simple, but definitely possible: after 2 weeks of 2-hour almost-daily practice I've acquired quite decent skills at that.
I was sitting face to face at a table with a contact at my bank and all the time she was writing the numbers and diagrams facing me. I said that i was very impressed with her writing so he told me that writing backwards was actually part of their standard training at that bank, because they all have to write things on paper while facing customers like this so often :)
