Disability equipment is normally really expensive, but if you look for things able bodied people do that occupy their hands (bike riding, car driving, mountain climbing), you can find loads of cheap, well designed kit you can repurpose.
The Camelbak is a great example. It’s a backpack with a water bladder inside that is sold in bike shops all over. It’s worth checking those first to see if it’s on sale. You can get different sizes, but we use the 3 litre version and we attach it to the head of the bed with a slip of velcro. That way anybody can easily pop the big bite valve into my mouth and I can drink as much as I need to. I can lay it on my pillow if I’m on my side and drink whenever I like, unaided.
You can also attach it to the back of your wheelchair and have the tube positioned on your wheelchair so you can reach it throughout the day. There are posable tubes but I don’t get on with them myself. Being hydrated is incredibly important for skin integrity and using a Camelbak has made this much easier for me.