بسم الله الرحمن الرحيم
Supplicate for your bahnoi wholeheartedly that he quits drinking wine. Also ask pious persons to supplicate for him. Recite the following dua forty times daily and blow it on water and give him to drink:
وَوَجَدَكَ ضَالّاً فَهَدَى
Also send him in jamah for one chillah. It is hoped that he will quit this bad habit.
Allah knows Best!
Darul Uloom Deoband