Algunarubia

What does your wife think of this? Because forget the merits of any of her overindulgences,she’s telling your kid to keep secrets from you, which is absolutely beyond the pale. What really matters though, is you have to get on the same page with your wife about this; if she doesn’t see the problem, you actually have a marriage problem, not an in-law problem. If she sees the problem but is too chicken to stand up to her mother, you need to help her find a spine.

For your reference, the part of the Ferber book you probably want is the “How to Solve the Problem: The Progressive-Waiting Approach” in Chapter 4 (Sleep Associations: A Key Problem). The rest of Chapter 4 is useful, but the preceding information is more to explain why sleep training is good, and the information after is for details if it doesn’t go well.

I think the best way to approach this is always by saying something like, “This method worked for me” or “I’ve heard that some people do x”. It’s best to offer a suggestion of a possible solution rather than using “You should” phrasing. With this particular problem, I’d just hand over the Dr Ferber book so they can read the chapter themselves and understand why sleep training is beneficial.