HI to all,

My question is about a petition by my Uncle to my mother. It was called i think F4 petition. It was filed last Sept of 1987 and it has been 21 years now and still, no visa available from the NVC. My mother is 71 yo. Shes been here to the USA last year as a visitor visa (multiple entry) and just recently returned back home. I would like to know how long does she need to wait more to be able to hear from the NVC?

Thanks a lot.