Memos
I thought pointing out that two out of three statements were complete bullshit was good enough.
You have no idea what memos may have been written during WWII on prisoner treatment, what policies were discussed at what levels, or anything else. Neither do I. It wasn't that kind of time.
I find it hard to believe that a wartime president who would put an entire racial group into internment camps would have gotten squeamish about ill-treatment of SS and Imperial Japanese prisoners, but that's speculation, not evidence.