If she makes enough money, she can sponsor her parents without you on it. That depends on the poverty guidelines, etc.
The affidavit of support is only for public charge issues not like an accident, he can get a ticket, sue,etc and only him will be responsible for his actions.
You can check this:
What are federal means tested public benefits?
Federal means tested public benefits are the following:
Food stamps
Supplemental Security Income (SSI)
Medicaid
Temporary Assistance for Needy Families (TANF)
State Child Health Insurance Program (CHIP)
What assistance programs are not considered means tested public benefit programs?
The following types of assistance are not considered means tested public benefits and do not have to be repaid.
Emergency Medicaid
School lunches
Immunizations and treatment for communicable diseases
Student assistance to attend colleges and institutions of higher learning
Some kinds of foster care or adoption assistance
Job training programs
Head start
Short-term, non-cash emergency relief
