They've done the endoscopy and there's nothing they can do but wait for now.
I'm told it didn't make it to his stomach and they don't believe his lungs themselves, small favors, but did his mouth, throat, voicebox, esophagus, and "windpipe" (though I don't know if my dad meant the trachea itself or just to the point of the larynx). I made a point to ask if the doctors had mentioned anything specific and he told me there was talk of a possible esophagectomy which is what I was fishing for and afraid of hearing as the response. The plan at the moment is to induce a week long coma, which as my dad phrased it "raises a whole new set of complications", and preform a second endoscopy at the end to see if there's improvement.
Sit and wait...I know it could be much worse but it doesn't feel like it at the moment.