The Child in Time question

In my edition page 211/220 when Stephen is almost back at his wife's house near the pub where he 'saw' his parents;

'it was then that he understood that his experience there had not only been reciprocal with his parents’, it had been a continuation, a kind of repetition. He had a premonition following instantly by a certainty, borne out of Thelma’s smile and Edward’s instant understanding of the months, that all the sorrow, all the empty waiting had been enclosed within meaningful time , within the richest unfolding conceivable. '

I am not sure what is meant here;

1)I don't really understand what his experience of his parents conversation at the pub has to do with his current situation,

2) What is the premonition leading to certainty? He doesn't seem to know what is going to happen when he gets to Julie's.

3) Is the reference to the time that has passed saying that this was necessary for his recovery from what had happened?

Thanks.