Thank you for the suggestion - however the device has a cord connection - this would simply not work for my mother, and possibly anyone with dementia : she will simply not be aware that the device is there to assist her hearing. So she will pull it off.
The only thing I imagine which would definitely work is as I described - basically over the ear headphones [ ‘Walkman’ or similarly lightweight ‘cans’ -but fitting comfortably on a cushion OVER, not IN the ears ] which incorporate a microphone and amplifier in the bit of metal or plastic connecting the two headphones and sitting comfortably on the top of the head.