For most men 25mcg of cytomel is what we would naturally produce daily. It takes a period of time after use until our body stops producing our own (spelling) triiodothyronine. Usually suggested towards 2-3 weeks...
It sounds like she has hypothyroidism....opposite of hyper which is over production.
Assuming her doctor is using t3 as a replacement to put her in normal range, we can also assume she is 'normal' I would be interesting in seeing her diet....she probably just needs to change her macronutrition around to shift fat deposits.
I have found personally....if you eat low carbs, moderate fats....longer multiple sessions of low intensity cardio is best to shed fat. Vice versa....if you eat a higher carb diet, lower fat intake we need to use a much higher intense cardio.
The reactions are completely different.
With higher carb diets, we are just doing higher intense cardio to use stored glycogen as an energy source, putting us in a deficit of calories from our base metabolic rate.
With lower carbs, moderate fats, we are targeting fat directly by using ketones as an energy source.....assuming we are in ketosis. You can purchase a keto stick from most pharmacy's to test this.
Try added some L-Carnitine and Green Tea to mobilize fat a little better.