Congenital vs injury

Hi,
My question is, I am trying to get a TBI waiver for my son. The social worker has said that my son has congenital brain injury? I have always understood that it was aquired, or brain injury?
I adopted my son when he was 7 1/2 months old. I have no way of knowing what happened to cause our issues (he started presenting with seizures at 6 years old) We had an EEG done at that time and this is what it read.

The First EEQ report I have from 1992 states,
"The CT scan showed an old area of encephalmalacia in left parietal occipital region."

Would this be due to a brain injury after birth, and not a congenital issue?

Thank you in advance.