I read this graphic novel, along with Persepolis, because I'd read that both books had been challenged by parents when it had been assigned in school to their children. I think I'd read that Persepolis was objectionable to some parents because it had swear words (an objection that has also been raised about Huckleberry Finn). I didn't notice any swear words; they may well have been there but I didn't notice them. Of course, I read Borstal Boy when I was 13. I found Borstal Boy difficult to read: there's a lot of Cockney rhyming slang: china is mate (china plate), fag-ends were cigarette butts, and screws is what the warders were called. I think someone who's read Borstal Boy is not going to be too intimidated by Persepolis, which is a sweet, funny book. In fact, I read John Hersey's Hiroshima the same year.
Maus is a wonderful book. It's mostly about Vladek, Art Spiegelman's father, who survived Auschwitz. There's a scene (I remember it all only inexactly) where his family is going through selection, and his father is spared because he's personally known by the man making the selection, but his daughter (Vladek's sister) and her children are selected, and Vladek's father climbs over the fence so that he can be with his daughter and her children, thus sealing his own fate. In the second volume, Spiegelman's character speculates that his father, who showed tremendous ingenuity in Auschwitz and even managed to smuggle food to his wife in Birkenau, "survived" Auschwitz and in so many ways was lucky (his brother survived, his wife survived, he was able to do jobs for the Polish and German guards that got him extra rations) but whose mental health suffered because of the trauma he experienced.
When I think about parents wanting to protect their children from the vicarious, empathic pain they may suffer from Persepolis or Maus, I feel sympathetic. I personally think that it's a shame, however, because I think the way that these books engage empathy is terrifically valuable because adult life is full of situations where competing values need to be evaluated. In short, if reading these books cause sorrow (and Persepolis, though it is challenging in some ways, is funny and engaging), I also think that they have great value.