How nice of you to reach out for your friend.  I might suggest looking into moldable wafers.  I also have arthritis in my thumbs (having surgery for it in a few weeks), and have found that the convatec moldables are SO much easier on my hands, and easier to shape/fit around my weirdly shape stoma than cutting.  You can get samples by calling convatec and discussing with one of their nurses.  Let me know if you need their number and I'll dig it out for you.

The only thing I can think of that might help is to wear a surgical glove when trying to cut her appliance. I have a K-Pouch and use a catheter. I also have arthritis in my hands but if I remember to down a glove it does give me some extra support. I hope this helps. Laura

Convatec is a great company and their nurses are very helpful, supportive and willing to send samples to patients