I would imagine that this was Jane's way of trying to hang on to some sort of autonomy when she was so limited in her ability to enjoy a normal life. And the games might well have served as some measure of escape from the harsh realities she was facing.
But whatever the reasons for her spending, I can imagine your shock when finding those expenditures. And I'm sure you're right about how you'd have felt later if you'd grumbled about them at the time.
Thanks for sharing this. Food for thought for anyone who might be dealing with a partner who is ill and facing the same kind of scenario.