Re-reading his post, i've identified what it is I was so hurt about.

Father, he wrote that he's been neglecting You, that being with his friends reminded him of the relationship he once had with You. that hurts so much. You know very well i don't wish to judge anyone's spirituality: but if he's been worshipping You all these time with me, how can I take his relationship with You away? Was it not real? Does my relationship with You not bring him closer to You too?

How could i be so wrong... Fallacy. All fallacy. How can i remain his friend? How can i?