When I was selling and fitting hearing aids decades ago, it was a legal requirement that one is thoroughly trained in the very delicate work of accurately measuring and fitting these devices. Incorrectly fitted aids can permanently damage hearing.
One of my co-workers was a Christian woman.
She had a habit of prescribing hearing aids for completely dead ears and to healthy ones as well. She carelessly filled a guy’s ear with a firm fixing mould material without first taking proper precautions which saw her digging the plastic out of his ear for a few hours. The boss sacked her and the client sued her. She blithely insisted it was none of her doing. The equipment the company supplied was faulty and the client had pressured her to finish her work quickly and besides Jesus forgave her.
She indeed was a “most vile miscreant”.
I add that this was well before digital hearing aids configured by computers against digital measured hearing tests to best accommodate hearing losses - I was working in a totally manual and analog environment which called on more skill and experience than technology. I recommend considering hearing aids for anyone who has a hearing issue. It’s a very safe market these days accomodating very specific hearing needs. (no I havent been paid for this)
I forgot to add we were paid on commission, the more aids sold the more money.