Obvs your friend is wrong. But I know you know that. I think cameras should just be banned from such memorials. If you go, you never forget parts of it. You don't need pics.
I've not been to Auschwitz but I've been to other places. As a young adult, several decades ago, I visited Dachau on a scorching hot day - was struck by how unprotected to the elements prisoners would have been. And the huge expanse of ground that was involved.
More recently - a few years ago - I visited Buchenwald. Yes, harrowing but I am glad I went. I was alone - which was preferable for me but I am quite a loner. Because it was more recent, I'll tell you what has stayed with me most. The building where people were tortured - it was 'cleaned up' but still evoked how it might have been. And there were incinerators there too. I walked over to the rail 'station', only a short walk from the camp perimeter. Still a platform and 2 sets of rails I think. I stood there alone just thinking about the people who made that journey. The fear and anguish they must have felt. I've seen enough films and read lots on the Holocaust and it was easy to evoke the idea of the place when it was in use. On the day i wasn't able to visit the secondary camp (dreadful joint pain) through the trees, or the clock memorial. At Buchenwald there were very many political prisoners, some Jewish, some not.
Something that struck me was the remains of a zoo near the top perimeter fence of Buchenwald. It was built to entertain the children of SS officers. Such callous irony in that.
At B'wald there was an amazing art exhibition in one building. Work done both by prisoners and also by survivors post-war. The imagination put into finding materials whilst in captivity was astounding, often just drawing with twigs and mud. Sadly there would have been copious mud.
There are memorials to ALL the groups who were in there. I'd say up to 20 groups. Both times I saw some people very upset. I can't recall photography - except while I was at the train platform, a man in the distance photographed the station. I imagine I am on somebody's FB now. I did feel a bit annoyed he didn't walk right over to look 'properly'. But his choice.
You don't have to leave the UK to learn about the Holocaust though. One part of the Imperial War museum in London has a Holocaust section. I went with ds1 when he was mid teens.