Avi85

I discovered this thread as I am in a similar situation. I did a tremendous amount of research but unfortunately, there isn't a lot of clear information available that caters to people in this situation, forcing many us to make risky assumptions.
I found this article on healthcare.gov website which might be interesting to some of you:
https://www.healthcare.gov/immigrants/lawfully-present-immigrants/
In this article, the part I would like to highlight is:
"Applying for Medicaid or CHIP, or getting savings for health insurance costs in the Marketplace, doesnt make someone a "public charge." This means it wont affect their chances of becoming a Lawful Permanent Resident or U.S. citizen."
From this article, I can conclude that while receiving subsidies on the health insurance premiums for one's parents would not breach support agreement with USCIS, I am yet to find out if the parents in this situation can file a zero income return. What I did find, however, is that parents can be claimed as one's dependents for tax purposes, only if:
1. The sponsor is providing more than 50% of parents' total support.
AND
2. The parents made less than $4050 in 2016 (IRS revises this amount every year).
Source:
https://turbotax.intuit.com/tax-tools/tax-tips/Family/Rules-for-Claiming-a-Dependent-on-Your-Tax-Return/INF12139.html
While #1 is straightforward, #2 isn't as much. The IRS encourages (I want to say required but I am not certain) a tax filer to provide a breakdown of their worldwide income. If one's parents are residents of the US but receiving income in forms of pension or annual dividend on other investments totaling more than $4050 in 2016, they cannot be considered as dependents and according to IRS, they will be required to file a tax return on their own. Theoritically, they could use that tax return to receive a subsidy in the health insurance, which according to ACA, would not be considered against the affidavit of support.
Feel free to share your thoughts. I am not trying to find any loopholes. All I am interested in is to get a clear understanding of the law to help me make a right decision. Since all the officials that I spoke with and the websites I navigated through seem to give conflicting information, there isn't a lot of credible resources available for people in this situation. If any of you find more reliable information, please do share.
And to the original poster, a big thank you for starting this thread.