The query posted above seems to have a lot of extraneous information postred along with it, that makes understanding the post difficult.
If you mean that your wife has allergic rhinitis and mean to ask whether in her condition with myasthenia gravis and renal failure along with renal cysts(?) a thymectomy would help?
IF that is what you meant to ask, a thymectomy would help combat her allergies as she appears to be allergic to quite a few substances.
However, you would need to discuss the option of a turbinectomy (removal of hypertrophied nasal turbinates) which is a relatively minor surgery to help deal with the rhinitis, with her surgeon.
It is possible that she does not have a good quality of life with her existing illnesses and therapy that she is on. So you will need to make an informed decision on how seriously the thymectomy will help and whether it is needed in view of the complications such a surgery can cause.
Do keep us posted on your doubts and progress.