She was angry but insisted she stays with him, loves him and wants to help him.
She can't help him. She can no more help him quit than she could help an alcoholic quit.
All that will happen is that he will make promises, break them, say how sorry he is, repeat ad infinitum, she will become his enabler, & increasingly enmeshed with a man who lied to her, pissed all over their shared dream, & cared more about his addiction than her happiness.
She will live a constant nightmare of trying to keep on top of his access to money & spending habits, & his gambling will take over her life. If she gets properly enmeshed, it could also end up costing her her own savings, or this month's rent money, or the holiday fund she'd saved ...
I doubt she'll want to hear that right now, but she needs to hear it. So maybe not directly from you, but from an organisation like Gam-Anon, which supports relatives & partners of gamblers - gamanon.org.uk/