Are there special types of bedding and mattresses to prevent bedsores?

Yes. The most simple & economic mattress is the egg crate mattress of foam which shows a surface similar to the containers of the eggs we get at the supermarket this prevents parts of the surface to be in direct contact of the skin. There is a sophisticated expensive bed called clinitron(r) than some hospitals use for the deeper ulcers and sickest patients. I mention before paddings & pillows.
Yes. Home health nurses are a great resource. But no mattress is perfect. Turning, shifting weight is also very important. If the patient is unable someone must help them. .
Bed surface bedsore. Yes, there are specialized mattresses and beds that can be used to help prevent pressure ulcers. Despite many studies, all we can say for sure is that any of these is better than a standard mattress; and none of the special surfaces, except for a few highly specialized beds, replaces offloading, frequent turning and common sense in prevention.