My aunt sponsored my mother (and family) under F 4 petition in 1991. My youngest sisters (twins, born in 1975) were under 21 at that time. My mum got a green card last yr and my dad was also allowed to come with her but he passed away in 1995. Is there any chance that my youngest sis get visa at the same time? Some say that they were under 21 when the application took place so they should get the visa with my mother. is that true?