falling bunny

I have a 10 yr old dwarf Netherland bunny. 2 months ago started falling over and not able to get back up. Took him to vet and went on mmedication for ear infection. He lost a pound...only a three pound bunny. He isnow eating,drinking, and pooping regular,and on critical care. He still falls over a lot,especially at night. So I sleep by his cage. He has free access to the house but have closed doors so less rooms for him to get in trouble...any ideas what else I can do

Though an ear infection is one possible cause for loss of balance in rabbits, there are a few other common causes as well. E. cuniculi would be one, but for a rabbit that age I would be looking very closely at age related arthritis and spondylosis. Where these ruled out by your vet?

Arthritis can be a common health issue for older buns, and they can cause a rabbit to have difficulty hopping and losing balance, among other problems. This happened with my 10 yr. old rabbit. She was put on daily meloxicam(anti inflammatory) which helped quite a bit. Another med that can sometimes help with arthritis related issues is adequan injections. There are also some joint supplements that have been used to help with arthritis in rabbits.
http://www.medirabbit.com/Safe_medication/Neurolpetic/gabapent_effects.pdf
http://www.medirabbit.com/EN/Bone_diseases/Osteo/arthritis.htm
http://wildpro.twycrosszoo.org/S/00dis/Miscellaneous/Osteoarthritis_rabbits.htm

If it is arthritis, getting the pain managed with medication can also help with getting weight back on when weight loss has occurred, as the rabbit is feeling better, able to move around better, and so can eat more. Some other things I did for my old rabbit to help boost calories, was to gradually add in a small amount black oil sunflower seeds. I also started feeding a small amount of alfalfa hay as it's high in protein(not for buns with kidney and bladder sludge issues). I know some people will use plain rolled oats to help with weight loss issues in buns, but I found it caused mushy poop for my rabbit so didn't continue to give it. Just with any new foods in the diet, always start with a small amount each day and gradually increase to minimize gut upset.

Even if it isn't arthritis that your rabbit has, I would still want a rabbit with balance problems from an ear infection or e. cuniculi, to be prescribed meloxicam as it helps reduce the inflammation that is causing the loss of balance, which can also help prevent permanent cell damage from occurring. So if your bun wasn't prescribed this, it is something that I would request my vet prescribe as well.