What were the Nazis doing in the
insane asylum?

They were experimenting on patients and euthanizing them

Explanation:

Nazis took a hospital that was insane asylum originally and made a place for medical experimentations. Medic Ray Leopold says he witness horrible things there which affected him greatly.

The insane asylum which he talks about was a psychiatric hospital turned experimentation and euthanasia center. One of the victims of the nazi regime were mentally ill people. As Germans wanted to keep the pure race, they wanted to get rid of all the people who were “faulty” in any way.

They would sterilize and kill people in the hospital who suffered from mental illnesses. After the war, it was estimated that more than 200 000 people were murdered here, plus many more at other places. Almost all of the German population who suffered from schizophrenia have been murdered.

this isn't a question and if you're going to list things be kind and use commas.

what does your friend need with?