Karter has a number of goals at school right now that we are working on at home as well. One of his goals was to hold his cup with assistance from the teacher or from us (hand over hand).
A week or so back, he was sitting on the couch and I set him up with his cup, hand over hand. I had to grab the phone so I let go of him so I could walk away and he continued to hold the cup on his own.
He ended up drinking the entire thing on his own! He did it again the next day. He can do it if his arms are well supported behind him however in his wheelchair, there is not enough support to make that possible. Right now, at home we are working on this and are thrilled at his progress. Here is a picture so you can see for yourself.