Why my grand-father spoke with a russian accent

I was raised in Brighton Beach, Coney Island. I loved the place as a child because of his continuous mixed smell of cheap frying oil and cotton candy. Ocean parkway was our week-end stroll. I always preferred the atmosphere of the fair in springtime. Everything was still closed and it gave to the attractions a sense of end of the world that fascinated me. We would stop by Nathan's with my grand-father to have a hot-dog. He said it was the best he ever had in America. This declaration puzzled me deeply because I knew he never went anywhere outside New York.
He arrived in Brighton Beach at the end of World War II, an immigrant from Ukraine. life wasn't that easy at the beginning, it's only around the 70's with the second major wave of Russian immigration that he kind of felt more at home. Russian restaurants and night clubs opened, you could eat borsch and blinis, read the daily Novoye Russkoye Slovo and hear your mother tongue again.
I think I never realised how hard it had been for him. He never spoke Russian with me, he said that he wanted me to be a real American. I saw him cried once, the day of my biology graduation. I think he knew at that time I would leave them all for a life of my own.