How to proof that his uncle is guardian without any official papper work done?

Please do not take my answer to your question to be specific legal advise to it, since there is no attorney-client relationship between you or the person on whose behalf you inquire. My answer should be viewed only as general information to your question. It is important to know if the young adult, when declaring his uncle as guardian in the abscence of his parents, was over 18 years old and of sound mind. If the young adult was under 18 and/or was mentally disabled when he declared his uncle guardian and there was no court order or power of attorney from his parents to the uncle giving the uncle the guardianship powers, there is no proof and there is a problem provint to the school the fact. If both parents (or the parent who has legal custody by court order) gives an affidavit today, showing the parents (or parent who has custody) had granted physical and temporary legal custody to the uncle when the young adult was under 18, that may be accepted by the school. I hope the answer helped. Alejandro R. Lopez, Esq. Attorney licensed to practice in Florida only Law Office of Alejandro R. Lopez, P.A., 2996 Edgewater Drive, Orlando, Fla. 32804 Ph.: (407) 649-1404