This story touched me deeply, and it really reminded me of the passage you quoted. It's sad to see how addiction can return even stronger, as if the empty space inside a person had been left unprotected. Sometimes, even after quitting, if the root of the emotional, spiritual, or psychological problem isn't addressed, the person remains vulnerable.

Returning to addiction doesn't make rational sense, but addiction doesn't operate logically. It operates through pain, emptiness, and escape. Perhaps, in that weak moment he had, gambling was his way of trying to numb himself from something he didn't want or know how to share.

I think your presence, your contact, can be a light for him. Even if he doesn't want to talk now, just showing you care is a step in itself. And perhaps, over time, he'll be able to fill that space with something more solid than gambling.

I think your return to his life is a good thing; it might even be a good thing for both of you.