What Causes Loss Of Body Balance Along With Hearing Loss?

My co-worker’s wife, approximately age 60, began losing her balance about three years ago. She fell several times once breaking parts of her hand then twisted her knee in another fall. She began to lose her hearing when the balance issue was going on. She has had hearing tests and now wears hearing aids. She is in a wheelchair and receives therapy weekly but it seems to me just the symptoms are being addressed, not the cause. I have told my co-worker to bring her to a larger facility to receive more in-depth care. I’m trying to help him (and her). thanks for any input.