Jan,
On the cost issue, I figured out that if it works for four years, a $2400 hearing aid is $50 a month. That's less than some people pay for their cell phone or cable TV, and I think hearing well is easily worth that much. But you know that, you have a BAHA.
My father had a pair of the older style hearing aids, which he ended up not using all that often. I think that is a mistake. If you get the small, light, high-tech ones, meaning the expensive ones, you can wear them all day every day, except when snowshoeing, etc. You are far more likely to get used to them if you do that, and then you start to get the real benefit.
The first day they are not so easy to wear. When I left the audiologist's office, I had the little kit in a plastic bag, and as I rode the elevator down, the crinkle sound from the bag seemed ridiculously loud, and I was tempted to return it right then. My keys, my door lock, every sound seemed to jump out at me. But the brain can adapt to that, and now my voice sounds weird to me when I don't wear the hearing aid.
I hope you can manage to get your mother to give them a real shot, I'm sure she would enjoy them if she can get past the initial adjustment and the cost.
Steve