Let her express her feelings on this issue for the time being, he can listen and reply accordingly if necessary.
He has already apologized, he doesn't need to continue apologizing over & over again for the same thing.
If he continues to text her and explain what he's done, telling her he's sorry for his part in making her feel that way, etc. etc. etc. after a while it comes off as pursuing, wanting to change how she feels, excessive communication and right now she wants to be the one talking, she wants to vent.
Throughout all of this, I would very much prefer no texting or emailing, dsh just tell her if she wants you guys can discuss this in person face to face later today, txting is not very personal when it comes to communication like this.
