An adult if he/ she is blaming a child for his/ her own mistakes and failures is a person who is not taking responsibility as an adult.
Will give you an example to understand how it’s sounding.
The most common is “Because of you…”
Example: mother blaming a child for how much she needed to spend on the child but neglecting to admit her own financial mismanagement.
Or blaming a 2 years old child who took a valuable item and brake it. Can’t admit that it’s an adults responsibility to look after and prepare environment.