The I-864 is intended to be a binding contract with the federal government to reimburse it if the immigrant seeks public benefits. The contract remains even if the marriage splits up. You should carefully review the instructions to the I-864 and seek counsel before deciding whether or not t sign.
Scott D. Pollock
Theoretically, the person can come after you directly for support even before seeking public benefits. I haven't seen this happen in practice, since it would be very difficult/unusual for someone needing that level of support to find and retain a lawyer for this.
Please see my Joint Affidavit legal guide on Avvo - link below.
Your daughter is likely the direct Petitioner for your son-in-law. If her income is not sufficient then she will not be able to petition for her spouse unless she also finds a co-sponsor which is why the request to you. As co-sponsor you woul dbe liabile after your daughter until your son-in-law eithr becomes a U.S. citizen or has 40 quarters fo social security time. The I-864 is a contract with the Federal government that you wil reimburse them if your son-in-law ever applies for means tested benefits and your daughter does not have enough money to reimburse them.
Lynne R. Feldman, Attorney at Law
Concentrating in Immigration and Nationality Law
2221 Camino Del Rio South, Suite 201
San Diego, CA 92108
phone: (619) 299-9600, facsimile: (619) 923-3277
Formerly Adjunct Professor -- Immigration law
University of Illinois College of Law