This is a fascinating topic made more important by California's passage of a physician assisted suicide law. Given that this is such a sensitive topic it may be worth conducting longer "test" interviews with subjects from this population prior to conducted your main interviews. Another possibility if this is not feasible is to at least talk to people in Chinese, African-American, and Hispanic communities (even if it just other healthcare providers with these cultural backgrounds) about how these issues are viewed and talked about in the community. This may help you avoid any unintended cultural faux pas during the actual interviews. It may also help guide the questions you ask early interviews since you have a limited time in which to address this topic.