Hypothyroidism

First, I find it odd that someone wouldn't want help with their condition. It's not like Hashimoto's is a sexually transmitted disease or anything.... If someone wants help they should be able to discuss relevant details of their condition with you to help you treat them. If they will not, you probably shouldn't treat them. This is certainly not meant as a punishment or anything, but there is a give and take between patient and practitioner that must be present for healing to happen. Her reluctance to talk about her condition is in some ways her reluctance to heal or at best her lack of trust in you as a practitioner. Either way, without her mind into the possibility of you helping her, she most likely won't be helped.

Second, you mention you use hara diagnosis and pulse to form a treatment plan, which is great. Then, however, you mention that you should "treat her immune system". Not "treat her kidney qi deficiency" or some other relevant finding that you have come up with from looking closely at her hara, pulse, and other information you've been able to deduce. In Chinese Medicine someones western diagnosis is only a fraction of what you use to formulate a treatment plan. You must look closely at her overall signs and symptoms, form a proper diagnosis, and then treat according to TCM, Japanese (whatever) style you are trained in.

As for your question about the immune system there are many loose corollary theories in Chinese Medicine. However, auto-immune conditions and immune system weaknesses are two different situations. We know this as people can have auto-immune conditions and still retain strong immunity from colds, flus and other common immune challenges. The Wei Qi is the defensive layer of energy in the body that protects us from colds and flus and those types of external invasions. Hashimoto's, however, has an auto-immune component arises from a certain level of hyperactivity in the immune system. The corollary of this can be Kidney Yin Deficiency or certain types of Yang excess. Deciding the root cause requires the proper use of the diagnostic tools such as tongue, pulse, abdomen, questioning, etc.

Within the Tam Healing system that we utilize, we often focus treatments on the following points for Hashimoto's along with other points as decided by their overall TCM diagnosis:

Huatuo of T1 (bone marrow), T2 (thymus gland), and T3 (lung/lymph system) - together these three points balance activity in the immune system generally and are useful for auto-immune based conditions.

Huatuo of C6 (thyroid)

SI 16, KD 26 (open circulation in neck and thyroid area)

Huatuo of T7, KD 3, and GV 22.

Hashimoto's disease is a complex condition to treat with Chinese Medicine but it can be treated with proper diagnosis and point formulation. Hopefully this response will help you to form a proper treatment plan. When you are treating complicated conditions it is in some ways more important than ever to stick with the basics. From a pure Chinese Medicine perspective there is no such thing as back pain, or hashimoto's, or arthritis, etc. There are only blood stagnation, kidney yin deficiency, or spleen yang excess, etc. This helps you to focus on what you are treating and not worry whether you have treated the specific condition before or whether it is a "difficult" or "easy" condition to treat.