What you’ll say depends upon whether or not you’ve already had contact with the bereaved. If you’ve already offered your condolences, or attended the visitation or service, simply greet the bereaved warmly and express an interest in their well-being. If this is your first meeting since the death and you’re in a public setting, it’s kinder not to bring up the death directly. Instead, say something like, “I understand these must be difficult days for you,” and perhaps ask about when might be a good time to visit, or suggest that you meet for lunch.