He said nothing. I said 'Is now a bad time or do you just not have anything to say?' He said 'There's just no answer, so I don't know what we're gonna do'.
His remark above does not imply ---TO ME--- what you got out of the coversation stated below.
The gist of the conversation was that he's not giving anymore on this issue
He said I dont know what we're going to do. using we is good. very good. he did not say deal with it or leave. he did not say, too bad, Im doing what I want.
Take his words at exact face value. Do not interpret. Just (trying) insight to him.
That means you have to be firm about YOUR boundary. How important is this too you? Tell him how important resolving this with both of your input is to you, calmly. Identify both of your desires and ask for solutions, while thinking of your own. Your both right.
let the teachers bring it too his attention, do not try to 'garner supportive advocates.' Let it come out on its own. Be a team, not adversaries, especially in front of others.