My advice, call her tonight and decisively tell her in no uncertain terms that is over. Do not make excuses. Do not beat around the bush.
I would not initiate contact. If she contacts you, politely state this "I believe it is best if we ________"
You can fill in the blank.
Do not justify your answer. Listen to her and validate. Then follow through with whatever your blank is.
I believe in this case, since it has lingered on for days/weeks, he needs to be decisive, proactive, and put aside his NGS. Call her. Tell her. Stick to it. Listen and validate when she objects. But end the call with her knowing in no uncertain terms that it is over.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018