How Can We Help?
Her son has a biological father she was married to. Can we get him a Child Visa?
Only if (a) you have his written permission for the child to migrate permanently, or (b) there is a court order removing his custodial rights.
Is this court order in the Philippines recognised by the Australian immigration? If not, what would need to happen to have it recognised?
The Department DOES recognize court orders issued by Philippines courts. Nothing needs to be done.