Feng had told the tales of his adventures to his servants a lot of time. Feng once jokingly told Dracula and Chandni that their mother is a Goddess. Hence, Dracula knew who his mother was.
"Ah, then goodnight master" Dracula replied while blazing with happiness. He was happy because his master had called out to him as a son for the very first time.
Dracula went back to sleep mode while wondering whether he will even meet his mother *The goddess of snow" in this life. It's because Feng hadn't told them that she had died. They didn't know that their mother was already in the afterlife.
Dracula went back to sleep mode and for the first time, he experienced a dream. Something that shouldn't be possible for a robot. A robot dreaming was something unheard of. One could infer that Dracula was already excluding signs of forming an artificial soul. Dracula was unaware of this knowledge and so was Feng.