Sorry. Mom should not now be assisting others, which is counted as "gifting" and could prevent her from getting care when her own assets run out. You are now sadly on your own. Good luck.
You may want to contact your Disabilities department in your county. Your state should have a Dept for the deaf. There maybe help to cover your aids. Call Office of Aging. They may know of programs out there. Some places will do a payment plan. Years ago they allowed you to rent, but not sure about that now.
She would still need an audiologist to fit them and adjust them. The "free" aid may not work with her type of hearing loss. Some maybe too old for the newer technology. Digital really doesn't last as long as the old annalog. Molds need to be replaced. So, there is some out of pocket. Not all health insurances cover hearing aids.
You say that your mom has Alzheimer's and dementia, sorry, she doesn't need to help you and I think that you are committing financial exploitation of a vulnerable senior if you get any money from her.
If your mother's in AL, you don't have full time responsibility for her care. So, is there a reason you're not working, or were you laid off b/c of the pandemic?
Time to take care of your own self.