Hello,
By the explanation of the project that you have put I deduce that you have the structure of the MVC design pattern. To make the controller correct apart from the typical validations of data integrity (type, length, mandatory fields etc ...), there is usually also a business logic. For example in your case, you can not report two diseases of the same patient.
Do you have a business logic?
And if you do not, would you like to create some?
Well, if you choose me, we can discuss these issues.
Sincerely