The simple way is to put an extra pilot on the flight deck. Unfortunately, this won't get a lot of support from airlines as it will increase the pilot numbers required, which means increased overheads. If forced to do so, the cost is likely to be placed on the travelling public. I appreciate the concern of the travelling public regarding 'nutcase pilots', and whilst this is (potentially) the fifth case of pilot suicide that I can recall, it's still not all that common. Perhaps research is required into the causes of this phenomenon; physiological stresses from long hours, marital stresses from being away from home for long periods, psychological problems from long term sleep disruption/deprivation, all can cause the kind of depression which manifests itself in the donning of a granite overcoat. Why such people insist on their passengers joining them for their final flight, I don't know but something needs to be done and the problem needs to be properly researched. However, the increased scrutiny of 'sane' pilots this is likely to bring may cause an exodus from the industry which could, potentially, open the door for more 'nutcase pilots' to come in.