In summary his sister is in doubt whether what she has seen was true or a dream.
Fast forward to sea side scene. His stepdaughter stated that she would be happy to be older sister and have a little brother or sister. However if he did not manage to impregnate his wife (her mother) she is ready to get preagnant with him because they are not blood related.
I hope I get this right. Correct me if I am wrong. It is ages since I've read anything in russian.