Alfresco does not have a concept for "complex objects". You would create this by simply modelling each consituent part / type, and then create (child) associations between them with the multiplicity you documented. A few years ago, the concept of "compound types" was on the roadmap, but it did not make the cut when Alfresco was prioritising its development effort.
I have created a case type having associationwith patient type and drug type. I have created a Model from the model manager of the type case. When When I goto the CaseModel Layout Designer, I am not able to see the attributes from the associations. (I case see only case number not the patient name or the drug name)