Psychedelic research is a really fascinating field, it is a shame there are so many social and legal barriers to research, as if research isn't difficult enough already. Changing these perceptions may be an important first step to realizing the potential of some truly amazing molecules.
I wanted to mention also that some psychedelics are perceived as providing a real death-like experience so that we can experience a virtual death before our actual death. Right now there is not sufficient evidence or research to suggest psychedelics truly do mimic what we experience at death, but it could be plausible. (http://wondergressive.com/death-solved-by-vestigial-gland/)
Lastly I wanted to touch on the issue of providing feelings of unity and connectedness without the use of psychedelics. I believe a lifelong journey of self discovery and fostering this sense of unity is the key to helping people come to terms with death. Death can be such a complex and difficult phenomenon, it seems like it would only be harder to confront if you wait until your near the end of your life. As many of the contributions pointed out, confronting the notion of death earlier rather than later can change how you live your life. The book "Letting Go: Pathway of Surrender" is an interesting proposal for self-therapy that seeks to push people towards inner peace. I just finished reading the book and would definitely recommend it to others.