First, my sincerest condolences to the OP. I know the route because the same change of aircraft has happened to us. If AA would provide for the extra overnight expense then it wouldn't be so bad. Unfortunately, AA only has to pay for the difference between coach seats and the seat you booked, and they define what that is. Do you know if there are any coach seats available?if you provide date/flight # info, one of us can look.

If there are no Y seats available, then AA has to provide IDB compensation, or get 3 other people to fly out the next day. Otherwise, you get a tiny refund and have to figure out who gets the nice seat. I doubt you'll be able to sit together in Y at this late date. Alternative routing probably won't be available now, either. First, let's see if we can find out what the status of seats is.