Parents absolutely can lose their "preference" and the best interests of the child standard permeates far more than just divorce cases (guardianship, juvenile, 432b, adoption). Whether or not that loss is forever completely depends on the circumstances. On the other hand, under guardianship law (pure guardianship law, without any overlay into 432b), the guardianship must end when a natural parent is found fit . . . although best interests may still come into play as to exactly how the guardianship ends (such as utilizing a progressive visitation schedule to eventually transition the child back into the parent's home).
Responses are for general information purposes only, and are based on the extremely limited facts given. A consultation with an attorney experienced in the area of law(s) indicated in the question is highly recommended. Information and advice given here should not be relied upon for any final action or decision, as the information is limited by its nature to the question asked and the fact(s) presented in that question. THIS RESPONSE DOES NOT CREATE AN ATTORNEY/CLIENT RELATIONSHIP, particularly considering that the names of the parties are unknown.
The two controlling cases in Nevada are Locklin vs. Duka and Litz vs. Bennum. If you are trying to regain custody of your children from a guardianship without an attorney who practices in this area, I fear you are making a mistake.
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