It's too big of a topic for a HN comment but do a google or LLM search and see. One widely-accepted aspect is that a child can not "self soothe" until 5-7 years. It's not developmentally possible, and using that language is a bit of a PR move to gloss over what is actually happening.

https://www.google.com/search?q=infant+co-regulation+vs+self...

https://en.wikipedia.org/wiki/Emotional_self-regulation

https://en.wikipedia.org/wiki/Co-regulation_(communication)

https://en.wikipedia.org/wiki/Attachment_theory

You should ask what she's basing that idea on. Maybe there's some research she knows about but the general world of public health doesn't? Seems more likely that she just doesn't know.