Info on health services

Hello everyone, I just discovered this forum about Tunisia, the country where my husband and I would like to move to in two years.  in fact he is retired but I still work.  we have already been to this country as tourists twice in the past in Hammamet and Djerba.  we decided to move there for various reasons: proximity to the country of origin (where we have small children and grandchildren);  the economic convenience for tax exemption of the pension also for me who am an employee of the PA (the only country together with Australia and Chile).  However, I am interested in knowing how the healthcare system is organized (something I have read is practically done privately because it is cheap).  but which city is best for those with chronic health problems to go to?  Hammamet?  Thanks for the info