Not every room at Port Orleans has room for 5 since not all have the pull down bed.
I am not sure that any of the accessible rooms (even those with tubs) have pull down beds. I
think there are a small number of accessible rooms that sleep 5, but if there are any, it would be a small proportion of the total number of rooms.
I believe all the rooms with pull down beds are in Alligator Bayou. I know there are a limited number of those rooms that sleep 5, so there may not be any available for the dates of your trip (accessible or non-accessible).
The Alligator Bayou area does not have elevators, so you would need to request a room on first floor and make sure they know the request is a medical request.
This is a picture from the Disney website of the pull down bed folded up - it's to 'seat' part of the TV stand. Having that gives you less storage space, since the area taken up by the bed would normally be storage.
And, here it is unfolded and ready to use:
Port Orlean does not have suites, so if you need a suite, you would probably be looking at a Deluxe resort, a Disney Vacation Club one bedroom, one of the Family Suites at a Value resort, or the cabins at Fort Wilderness.