Hi, Welcome to Health care magic forum.
Diabetes is a disease where the sugars are not absorbed int the tissues, and not stored in tissues, so when diabetes is not under control by medicines, weight gain is not there.
When she has changed the drugs, the sugar is under control means what ever she eats is absorbed into the tissues, and there is weight gain.
As a whole, it appears that she is taking more of calories.
I advise you to control the diet for controlling the diabetes and weight gain.
Minimize taking the calories, fats, fries, oils, ice cream, and junk foods.
Ask her to do any work in front of her, what ever the work may be .
Let her practice,
yoga, morning walk, etc.
Ask her to sleep for limited hours, let her practice late to bed and early to rise. Ask her to avoid day time sleep.
Wishing for a quick and complete recovery. Thank you.