The following is an extract from CNN. I'm wondering if it's okay to use "wasn't" ( or "weren't," if one wants to be formal). Why wasn't hadn't been used?
The family of five — including the girl and her two brothers, ages 2 and 1 — had been reported missing a day earlier when they didn’t make it to a Christmas Day celebration, Nine News reported. “If it wasn’t for the 5-year-old undoing the buckle of the 1-year-old’s car seat, he wouldn’t be with us today,” Read said. “She’ll probably not know for a few years.”
Note that the following is okay with had + past participle:
If the 5-year-old girl hadn't undone the buckle of the 1-year-old’s car seat, he wouldn’t be with us today.
Therefore, I find the use "it weren't/wasn't for ..." in the CNN sentence puzzling, as it relates to a counterfactual past event. I would have expected to see "hadn't been."
In Practical English Usage by Michael Swan, he mentions the following:
To talk about the past we use If it had not been for.
And offers this example:
If it hadn't been for your help, I don't know what I'd have done.
So, who is right? CNN or Michael Swan? If both are right, how do we reconcile CNN's example with Swan's account?