Answer:
(Fatwa: 189/190=B)
If the boy has accepted Islam wholeheartedly and you are satisfied with his Islam, also he started practicing Islam then the nikah of the girl with the boy may be valid with the permission of the wali (guardian).
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
