When you say your mother has "thyroid", does that mean she has hypothyroid? What kind of medication does she take? Does she take thyroid hormones?
Can you get copies of your mother's lab reports? It sounds like she might be on too high a dose of thyroid medication, but we can't tell without knowing what her hormone levels are...
If you can get a copy of her test results, please post them here, along with the reference ranges listed on the report for each test that was done.