Hitler was an evil man, if what they say that he did was true, and he no doubt had evil beliefs for sure. But if he left that, repented, rectified his situations than the door to forgiveness is always there. Unless you’re dead, and then it’s too late. 

But best believe, there wasn’t much of a difference between him and the likes of Winston Churchill. They all shared similar evil ideas. It’s just that Hitler lost the war.