New GC parents to file for their children?

[aph]

So I am a Citizen and filed for my foreign parents who are now GC holders. I have 2 siblings (my parents’ children) back in my home
country. Both siblings are more than 21 years. One is married with kids and the other is unmarried.

We are exploring opportunities to file for my siblings. The options I am thinking of now are:
1. Get my parents to file for the unmarried child because I read GC holders can’t file for their married children. The only issue here is that my parents have no income, so I’m wondering how they can file unless I become a joint sponsor.

2. I file for both siblings which can take a very long time, I reckon.

I am keen to learn if anyone has been in this situation and what did they do or can suggest. Perhaps there’s another option I am yet to even consider.

Many thanks

[newacct]

Either of your parents can petition the unmarried child. They don't need to worry about the I-864 Affidavit of Support at this stage; that is only needed at the stage when they immigrate, many years later when a visa number becomes available. At that time, you can act as a joint sponsor.

You can have both you and your parent petition the unmarried child if you want to be safe and are willing to pay the additional cost. A person can be the beneficiary of multiple petitions; they do not conflict. Your parent's petition probably has less wait for visa numbers than your petition, but your petition can act as a backup, in case the petitioning parent dies, abandons residency, or your sibling married before they immigrate.

[aph]

Many thanks