Please accept my condolences for your friend's death. It is obviously an emotionally charged issue for you, and this might be a difficult discussion for you. You should be aware that the intent of this forum is to analyze diving accidents and deaths to try to glean some lessons other divers can use to make their dives safer.
A lot of divers have expectations of their divemasters that are different from yours. For example, I do not expect, or want, ok signs, checks on air, buddy assignments, or even pointing out cool things. I am okay with dancing and jokes. I take responsibility for my own safety, but I do expect a briefing on the dive site that includes enough information for me to navigate the site and anticipate hazards like current or tide. If this information is not volunteered, I ask. Were these factors in your friend's death?