A high thyroid is not really a term used to describe any condition that I am aware of. It may be that your dad's doctor
meant that you dad has a high level of thyroid hormone, a condition known as hyperthyroidism. This is where the thyroid gland makes too much thyroid hormone causing symptoms of insomnia
, weight loss, and nervousness. If this is the case, then there are very good medications and procedures or surgeries that can correct this problem.
The thyroid gland is located in the lower part of the neck just below the cricoid cartilage (Adam's apple). The thyroid generally doesn't appear higher than this. When the thyroid gland is enlarged, it can appear to sit higher than a normal small thyroid sits. If this is what your dad has, then he will need some more blood tests to figure out why his thyroid gland is enlarged. I will say that since the term "high thyroid" is not typically used to describe an enlarged thyroid gland, it is more likely that his doctor was referring to the former possibility.
Your dad should schedule an appointment with his primary care physician
to discuss these issues. His doctor should be able to explain what they meant by high thyroid and discuss the treatment options if necessary.