@dyslexia,
Dys, you're talking about the response of the CPS. I'M talking about what she ASKED about - what SHE should do. That's all she can control - what she does. She doesn't like what's going on, she suspects there's abuse involved, so she's asking for advice on what to do. That's what I gave her - MY advice about what SHE should, in good conscience, do.
What the CPS or other authorities do is up to them and she has no control over it. They may or may not take it seriously. They may or may not investigate. But that wasn't the question.
My daughter is a social worker here in Canada, and in her jurisdiction they take every call seriously. If the story they get sounds like this one, they'd be out there the same day to investigate. With a police officer (it's the rules there).
And you can think my advice is 'knee-jerk' but I can't understand how you could. This is a little boy, a 2 yr old, for heaven's sake, unable to defend himself who has been heard being yelled at with suspected physical trauma. Are you nuts? Of course she has to report it!
I don't think she needs EVIDENCE, either. Here in Canada, you just need a suspicion, and if she's heard it, that's enough. If you wait for EVIDENCE, the child could be dead. How would you like that on your conscience? Isn't it better to be safe than sorry?
And I'm sure the CPS wouldn't take the child away for just being screamed at. I'm sure they'd ask others during an investigation - friends, family, neighbours - not to mention having a good look at the child himself.