Parental authority or child custody-illegitimate child

Hello po, I hope someone can help me. My child is bearing his bio-father's surname as he was aknowledged when he was born. We were not married. He did not give any support since he was 1 year old until now that he is 12 years old. My child is living with me and my husband here in abroad since he was 4 years old. My questions are, do I still have the sole custody until now that he is already 12 years old? If so, can I get a court order easily stating that I have the sole custody or do we still need to undergo the long process of hearing etc...to get it? Do we need an authority or certification from the bio-father that I have the sole custody?

I hope someone could help me. Thank you!

No need to go to court. since the child is illegitimate, you have sole parental authority of your child.

What kind of document can I get to prove that I have the sole parental authority of my child? A dociment which can be accepted internationally?