Just an update. I went down the route of requesting a seat upgrade through the government due to medical necessity. I even got a doctors note that I sent in. It seemed promising at first but I just got word back that the my approval process is fairly convoluted and that we probably won't have time to get it done. He actually told me that it would be easier to choose a new person to go and get them ticketed than to make an upgrade due to medical reasons.

Oh well, I tried. I'll see if I can get the gate agents to give me an exit row or something.

Thanks everyone!