Filing GC for Parent-BC question/issue!!!

[piyu7444]

---Posting for someone else who is unable to do this

I have acquired US citizenship and now I want to bring my DAD to US and then apply for his GC. My mom passed away recently. My understanding is that the following documents are needed to apply for GC:

1. Copy of birth certificate of the beneficiary (parents)
2. Copy of parents' marriage certificate (if filing for both parents)
3. Copy of parent's I-94 card - both sides.
4. Copy of parent's passport (entire copy)
5. Copy of parent's US Visa

Now we dont have a birth certificate for my dad. All we have is high school leaving certificate showing his birth certificate. WILL that work as secondary evidence when we dont have primary evidence or that could be an issue?

I am assuming that since I wont be filing for both parents a marriage certificate is not needed (#2)

Thanks
Piyu7444

[BombayChaPorga]

I think a marriage certificate is still required as that is the only way to prove that you were born to your parents in a wedlock.