How do you teach an 86 yr old how to drink out of a sippy cup?

You should use a sealant based Nalgene, like the one pictured here:
These ones are spill proof, and are perfect the elderly. I use them with my 90 year old grandmother and it works well.

Thank you Brenda, I also have one of those cups. The lid screws on and the straw doesn't come out. She manages to spill that also.
I know I'll find the right cup somewhere.

Hi there, I'm not sure how long she can hold a cup upright, but this is what I do with my mother. I buy those plastic cups that you see at Walmart, they have a lid with a straw. I have quite of few of them here..(I usually get her a new one every holiday-we just got her a Zombie one for Halloween :) My mother is able to hold the cup..her hand is just a little unsteady..but the lid keeps the liquid from going over the sides.
Good Luck!!! Everyday is a new learning experience to find what works.

Put some beer in her sippy cup.
Try putting a tiny amount of liquid in the sippy cup, just a mouth full and very carefully tip it into her mouth. Is she still strong and steady enough to hold a cup herself? If not it is time for the spoon which of course takes forever. But you can fashion a large spoon into an open funnel. bend up the sides of the spoon so it holds more liquid. Another way is to dip a straw in the liquid, put your finger over the end, then put the end with the liquid into her mouth and slowly release. You could also try a large syringe or turkey baster. have you actually tried demonstrating the sippy cup. Show her what is in it then put the lid on and take a sip. By the time you read this she is probably already sipping away!!!!

Can't do a cup with straw anymore. She spills it. So on to the next idea. Sippy cups are non spill. My mom always loved her beer!

Try a straw, something that is familiar. She didn't raise her kids with sippy cups. When I get to that point, give me a beer bottle, because I will never forget how to use one of those.