What is the function of religion?

[MindForgedManacle]

I have three questions:

(1) What are/is the function(s) of religion?

Put simply, social cohesion, comradeship and a digestable worldview.

(2) Should someone who does not believe in the truth claims of organized religions (atheists in particular) change his/her view towards religion if it is accepted that religion actually has beneficial function for a society that our secular age is in danger of destroying?

Depends on what you mean by "change his/her view on religion". Most especially, it would need to be defended that religion is the only such way to get the supposed benefits, and at the cost of knowingly entertaining falsehoods. Comparatively, should we go around trying to abuse the placebo effect instead of medicine simply because the placebo effect has some limited beneficial effects? Of course not, and the same goes for religion.

(3) How could these functions, if one remains thoroughly secular in one's ethics and thought, be implemented within a secular framework; should an atheist or a secularist develop a secular religion, and if so, what could it look?

I don't know really. Humanism is a possible route, but I think this sort of misses the point. Given our knowledge of our evolution and psychology, why should we bind ourselves to what we've evolved to be? This would be a blatant naturalistic fallacy, I think. We're also evolutionary predisposed to be rather selfish much of the time - which has benefits, mind you - yet we recognize that's just not something we should accept, and we rightly regard the abnormally selfish in a negative light.