Shame about your business, my late husband used to restore vintage lorries and I ran a national lorry club, not so much a business, more a way of life. They were very happy days.
It is NOT up to your sister to make decisions about YOUR life!!! What is she doing to help? Too many forum members have "helicopter" siblings who drop in now and then and are useless.
From now on, think about what mum NEEDS not what she wants, which can be very different. My mum was adamant she didn't want anyone in the house, she was very reclusive. I did more and more and more until I was diagnosed with a very serious life threatening illness. Then, and only then, faced with the prospect of carers in the house or a nursing home, did she agree to carers.
Mum really should be paying you something towards the care you give. My father in law was still saving when he died at 86, living in a draughty house because he wouldn't buy draught excluder as the landlord might benefit after he'd died!!! Is your mum out of touch with the cost of things?