Knitting a Mitten for the Disabled

I have currently been given the task to knit a young disabled woman a pair of mittens. The problem is that she has trouble getting them on, and I need a pattern that is very easy for a woman whose hands are not able to work to put them on.

The only solution I have come up with is to knit a mitten where the cuff is not knitted together in the round but has a magnetic clasp connected in a button-like manner that could connect the material firmly enough to keep her hands warm. She has very childlike hands that are very, very small. She also has fingers that are long and slender. I have yet to decide if a thumb gusset would be appropriate. I really need a pattern for a woman of this nature. Thanks in advance.

Welcome to KnittingHelp!
What a kind thing to do. I like your idea of the magnetic clasp which would be simpler to close over than a button and easier to work with than Velcro. Can you have her try on the mitten as you knit? That or several measurements may help.
Here’s a fairly generic pattern with thumb gusset: