One step at a time for him, 'Catz. I had an early morning text from Seth's Da. He was (is, truly) doing a bit better. Then, this morning he found a card to Seth in the mail from the girl's mother. She'd signed it only from herself, when in the past it was signed from her, her husband, the girl and the family pets.
That hurt him more than she'll ever realize, sending a card that made it unequivocally clear that things had changed so much.
He was afraid to give it to the boy (he's only five) because Seth is already very confused about why "she" doesn't come to their house any more and why they don't go to her parents home.
So, all that to say, one step at a time, but there will be backward steps too.