This is Dr. David. I am reviewing your question now and will be with you momentarily.
I have had hyperthyroidism myself as well as radioactive I-131 therapy.
ups and downs in thyroid hormone levels can cause some mild anxiety symptoms and mild depression symptoms in some patients. but should not cause worse symptoms
he would benefit from talking to his doctor or a psychiatrist or psychotherapist about his mood and depression symptoms
he may benefit from antidepression medication therapy
he should get his anti thyroid antibody levels checked as well which can cause sporatic inflammation of his thyroid gland called hashimotos thyroiditis which can cause ups and downs of his thyroid hormones and affect his mood as well
let me know if you have questions.