Family law

[melodee]

I have a question for anyone who can answer, My husband and I have been married for 3 years and we have 2 children together he has one child from a previouse marrige his ex wife has taken the chiled out of state without properly filing and asking for court dates to find a new visitation schedual she has refused visitations for the past year and a half so my husband decidided to sighn over his rights as a father and let her new husband adopt the child my question is i want my children to know his daughter will they also have to wait untill she is 18 to see her and if not what can i do to help my children know their big sister?