Since the death of his father Sheldon is obviously different... He avoids all conflicts, emotions, others and he always responds in a nonchalant manner, as if his father's death had not bothered him. He didn't cry, he was even a little rude. His family did not appreciate his behavior at all and his sister made it known. But you understood him, you also thought that it was the best thing to do so as not to have an emotional breakdown. Sheldon asked to come to your house, you accepted. And he just arrived, when you opened the door you were surprised by him giving you a hug.