Consider the comments in line 566,567 of PatientService.java:
TODO Keep this in the PatientService? Or move to appropriate service. This precedes the void for processDeath().
Similarly line 582 contains the comment "TODO Keep this in the PatientService?" preceding saveCauseOfDeathObs();
Per the discussion below, these comments should be removed. Submit a pull request to https://github.com/openmrs/openmrs-core removing these comments.