not an expert, but when it comes to 'social security' it's my understanding that you can only receive your social security payments before the age of 65 if you become disabled and are unable to work. similarly, if you die before the age of 65, your survivors are then entitled to receive your social security payments. also keep in mind you only receive social security payments if you have contributed to the social security program through payroll taxes (aka FICA tax).
i have a feeling your family is talking about something else besides 'social security' though. depending on what state you live in there are a number of programs that can assist with the cost of medicine. for example, i live in maryland, which offers the Maryland Health Insurance Plan. It's really amazing because anyone with CF automatically qualifies. There is no sort of financial barrier like Medicaid, which only allows very low-income individuals to qualify. it covers all of my CF prescriptions. I rarely ever have a copay. And even if i do, it's very cheap. I would check to see what sort of benefits are available in your state.
hope this helps