One of the classic (old school) criteria for radiation treatment was always "not a good candidate for surgery," so it does make you wonder why radiation is being ruled out. It may be because balance issues are not addressed by radiation treatment, and that is clearly a dominant symptom for DLM4me.
My concern here is that every case of recovering balance I have read about, after surgery or otherwise, has involved physical therapy and movement. I think the mobility issue is really at the top of the list; my gut says DLM4me, you have to get moving, one way or another. Canes, crutches, a walker, something. I think it is quite difficult to overcome a balance issue without moving around on a regular basis. Surgery can cut the bad balance nerve, making it easier for your brain to adjust, but you still have to go through some physical therapy and activity to get back in business.
I hope the pre-op consultation goes well, and that you get a good plan in place. If you are not cleared for surgery, there are alternatives. It does not sound like it is going to be smooth sailing, but there will be a way forward. We will be here every day to encourage you along that path.
Steve