Dad was having troubles turning over and out of bed due to blanket weight & getting tangled in them.

We tried satin sheets, the micro fiber sheets are slippery too so less entanglements, satin jammies..
seems to have helped for him.

I tried a microfiber comforter that I really like, thin and lightweight but nicely warm too.

If she gets chilly in bed another option is a memory foam topper, they are nice for comfort & holds your body heat in.
But if she has trouble turing over & getting in /out of bed it might not work well for her as you do sink into it a little.

We have a topper on our waterbed and don't even need to turn the heat on unless really cold weather hits.

There are clips or elastic bands that you can get to keep sheets/blankets in place better, that might help with some of the tanglement problems.