Detox Sorry about your Mum, she sounds a lot like my Dad in some ways.
Dad is fine after his ordeal - as my teenage son said many years ago about him "In the last 5 years he's written off two cars, had two heart attacks and pneumonia - he's indestructible". I let him talk uninterrupted this pm to the reenablement coordinator, to give her a glimpse of what we are up against, but she took it all in her stride. I guess she's seen a lot.
I used to grumble that if I dropped in for 5 mins to deliver a cake, I'd be stuck there 3 hours being talked out. Now if I drop in for 5 mins, I end up changing his incontinence pad, cleaning his bum and re-dressing his bedsores. Where did I sign up to this?
MrsBert you could try something simple like an Innocent smoothie - nice to drink and full of calories. Once they're getting really old, the guidelines on healthy eating don't apply in the same way. Anything that builds up to a bad effect doesn't really matter, because something else will have got them first. So her enjoyment comes first, quality of the nutrition second. They'd try to get my Mum to drink special high nutrition shakes for the elderly, but she hated them and refused to touch them.
Also think why your Mum is refusing food - it can mean the beginning of the end, as with my Mum. With hindsight, it would have been preferable to just leave her be. Same end result, possibly reached more quickly, but pleasanter for her than being nagged to eat.