Here are a few tips in getting your parents to the United States as immigrants.
1. Become a citizen yourself. If you are green card holder you can certainly petition for your parents to come over, but there will be a waiting period for a current "priority date." Thus, even if you have a green card petition for your parents approved, you could wind up adding two years onto the immigration process. If you are eligible to become a citizen, apply! Then when you petition for your parents there is no waiting for a visa to become available.
2. "Adjustment of status" is always faster than "consular processing". Adjustment of status means handling the immigration process in "one step" by your filing an I-130 alien relative petition and, provided your parent has been lawfully admitted or paroled into the United States as a nonimmigrant, having them simultaneously file an I-485 application to adjust status with the immigration service (USCIS). If your parent possesses a visitor visa and travels back and forth between the USA and the home country, if a decision is made after a lawful visitor admission to adjust status, this is the way to go. The process will take approximately nine months, during which time your parent will be able to apply for temporary work authorization and an "advance parole" should emergency conditions require them to return to the home country. Of course, if your parents don't have visitor or other visas that allow them to come to the United States in advance, you cannot consider this option.
3. "Consular processing." This is a two-step process because you are dealing with two different bureaucracies. USCIS for the adjudication of your I-130 alien relative petition for your parent, and then an entirely different process before the Department of State collecting documents (again) showing that your parent has the right to immigrate to America, and that you have the ability to support them all here. In effect, you go to the immigration process twice. First, you file the I-130 and wait approximately 5 to 7 months for it to be adjudicated (times vary). Then, second, file with the Department of State's "National Visa Center" (NVC) an affidavit of support (I-764) and civil documents together with an online visa application (DS-260). This process may take another 6 to 7 months before you get an interview date for your parent at the nearest consulate in the home country.
4. US Government Benefits? When your parents finally get here there immigrant visas will be stamped in their passports and they will be considered permanent residence. In a few weeks they will then get green cards in the mail from USCIS. However, becoming a permanent resident does not entitle a parent green card holder to immediate access to federal benefits. Except for certain emergency situations, they will have to wait to get their Social Security cards and numbers and will be ineligible for benefits for an additional five years. The best way to help your parents as they age and require assistance is to get them over here as quickly as possible.