My elderly neighbour had COPD and lived in his 3 bed semi to the end, with a stairlift District Nurses (?) visiting and dropping off oxygen very frequently. His family chose not to have home carers, but split morning and evening visits between themselves. They were very willing but it absorbed so much of their lives when some still had small children themselves. Only really possible if not working I think.
My own DM's situation is different. Middle stage dementia and living in her own small bungalow. She bought this 20 years ago when in mid 60's and it felt early to downsize, but it proved a wise choice as is now perfect for her limited mobility. Sheltered accommodation would have been even better.
Things that help us support her from a distance are:
LPOA -health and welfare and financial. Set up now and only à ctivate when needed. This could be years down the line or next week if your Mum is suddenly very ill or has an accident. For your Mum's reassurance she can write in the point st which she feels they should be used. For example if a doctor advises she is too ill to act for herself. Also get her current GP surgery to give her a form to complete so you can speak to them about her medical needs/care/test results/make appointments etc.
Local authority telecare service - they can provide fall wrist bands and pendants. We were also given a free automated tablet dispenser. There's a small weekly or monthly payment for the monitoring of the wristbands etc that can go out of your mother's account on direct debit. You and your sister won't have to buy anything. Later you can add chair/bed/movement sensors etc. They also do fire alarms connected to a call centre. All in with the price. For my mum it's £5 a week for Al, the telecare she has.
They won't do security cameras due to privacy/data issues. But with your Mum's consent you can put one in for example the hall and view/scan the area only when needed - if you think she's had an accident or fall maybe. Ours doesn't record so there are fewer data concerns. It's just drop-in (live) and also has a loud speaker so I can talk to her if fallen/lost phone. You could do something similar with Alexa. Our system can covers smart light bulbs and plugs so we can switch lights and heaters on remotely. The app was free and just buy the camera (£40), plugs (£8) etc on Amazon.
Age Concern - fit free grabrails etc. Also installed a free keysafe. This means you can give the number to emergency services or later on, carers. If she has a fall or illness, they're not delayed by smashing the door off to get in.
Carers up to 4 x per day. It might be too early for this yet. It's not a perfect system and standard is variable. Before we got to this stage I wish we'd investigated a cleaner and one of the meal delivery services that have replaced meals on wheels. Some deliver a hot lunch with 15 min welfare check and pop a sandwich in the fridge for tea.
Bins - contact your local authority. They can send you stickers that mean the refuse collectors will collect them and return to normal place. She doesn't have to do that herself at all.
All this won't work for ever but should mean that you and your sister are dealing with less day to day support and have more time to help her socially, or with real emergencies. Good luck!