You can choose from lots of window film patterns. Most will obscure the view from outside but if you choose carefully you can have gaps at different looking out heights.
Wilkinsons do this film. It is called static cling adhesive film and comes in either a frosted finish or with different patterns and you can buy it online from the Decorating and DIY department, with the sticky back plastic.
You can get window film that acts like one way glass. It means if its lighter outside than in you can see out but they cant see in. The only thing is if you put the light on at night and don't draw the curtains everyone can see in to your house clearly! It is on Amazon amongst others but be aware its not that easy to install without practise, its very easy to get bubbles or creases. If you can practised on a small window or even just a piece of glass first and follow the instructions.
There are several firms online which do self adhesive film. I've used it on some small conservatory windows to try and block out the sun. It does affect the light a little and your mum probably wouldn't be able to see out which might have been another reason she didn't like the nets. It's fairly easy to apply but for a big patio door you might need another pair of hands. Check out the videos on YouTube which are a good source of information.
My DM has dementia and lives in a ground floor apartment with a very large patio style window which is set slightly below street level. Does anyone know if there is a protective film I can put on the glass that will allow her to see out but stop passers by seeing in? I’ve tried net curtains and vertical blinds but she just trashes them saying they make the room too dark. I need to find something which won’t block out the light.