The Wikipedia link doesn't mention anything of the sort. And the other discussion just points to the same link / "proof".
On the contrary, it does mention that he helped save thousands of mental patients from the Nazis, and that he was held not just in Auschwitz, but in 4 camps (in which case, whether he was in Auschwitz just for "a few days" is irrelevant).
As for the "performed medical experiments on Jews himself", which makes him sound like Mengele, what he did was treat people including Jews who had attempted suicide. He used electroshock therapy and even lobotomy, but those widely used in the time, they weren't some nazi-like experiments (and up to the 1970s in the USA for example).
>and it appears his main thesis about attitude mattering above all else for survival in the camps is simply false.
That's just what some other professor said in some papers. Not some definite rebuttal. You can find papers against anything...
edit: Gee, you're right about the wikpedia page! The controversy section has been entirely erased since I last looked! Very weird. Sorry about that. e.g. in April last year it looked like
https://en.wikipedia.org/w/index.php?title=Viktor_Frankl&typ...
I guess all the references to things have been removed too. I'm not sure why. The books and papers it led me to seemed believable.
It seems Frankl has been somewhat exposed/debunked. Would you believe he was at Auschwitz for only a few days, performed medical experiments on Jews himself, and it appears his main thesis about attitude mattering above all else for survival in the camps is simply false.
https://en.wikipedia.org/wiki/Viktor_Frankl#Controversy
There was a bit of a discussion previously about that. https://news.ycombinator.com/item?id=21901602