Whatever you do, recognize you face a potential bear trap, complete with honey-like inducements.
Yes, she disclosed a sense of backsliding but that is totally different from doubting the organization. I notice you say she referred to herself as "lazy" - which suggests she still views it as "the truth" but is more inclined to find fault with herself. Danger! Be careful!
Any comment on your part that tries to widen the discussion to a change of focus about the organization will snap your relationship in two.
Empathize. Say it's understandable. Ask her what she thinks the solution is. Listen. Reflect. Say you'll always be there to listen to her. Keep your own doubts to yourself.
Fact is, the organization is full of Witnesses who are slowing down but who are still hostage to its teachings, who are still paralyzed and fearful of life outside the organization.
Don't mistake slowing down for doubting. They are two entirely different "conditions" - although likely relatable over time.