Some questions please

At night in Auschwitz- I don't know if it's correct, maybe I should write -during the night in Auschwitz?

I hear his voice - here should I add "would"? but then again I would hear in voice in my ear...

You know, how much good - here should I add "do" - Do you know? or it's ok to use only "you know"?

Thanks

"Do you know how much good you can do at night in Auschwitz? All around you, there are broken people."

"All night I sat up, listening, encouraging, and comforting - I stayed alive."

Even today I sometimes find there's no point to my life, I go into the sea, but then again I hear his voice in my ear;

"The greatest thing. . . ' You know, how much good can you do on the streets of Tel Aviv? "