Unless the chain of causality is interrupted somewhere I dare say that, generally speaking, "everything does happen for a reason".

Surely that expression is often used in contexts where the
reason is deeply meaningful to us humans. It can work as a mean to not loose hope and finding meaning in difficult situations, but it's more our interpretation of the circumstances and frankly I can't see how we would be able to objectively assess such statement.
I think the article tries to make a couple of good points but the general tone makes it sound more like a rant than a reflection on the subject of grieving.
If somebody can overcome a tragedy or loss via a "higher plan/reason" I would not go to him and scream "it's bullshit" to his face. And at times the author seems just to do that.
Similarly I wouldn't like someone to shove that option down my throat in a similar situation.
I don't know, in the end the article seems more like a tirade inspired by personal experience. It makes sense but grieving is a very personal process, there's no right or wrong way to do it, imho. From a purely rational p.o.v I can agree with the author's bottom line, though our psyche contemplates a lot more than just linear thinking.
Cheers
Edit: fixed the usual dozen typos
