NAL. This is not legal advice or any kind. Maybe your friend can try to reason with him gently.
Like kya bhaiya, aise kaise shaadi tod du? Engagement ho gaya hai, main to usse apna biwi maan chuka hoon. Aap k paas paisa, aur power hai. Aap log humare saath kuch kare to hum kuch kar nahi paenge. Lekin shaadi tod dunga to khud bahut guilty feel karunga, aur iske baad mujhse koi kaise shaadi karega?
Aap usse ache se jaante bhi nahi hain, thode time baad infatuation chala jaega shayad. Main shaadi nahi todna chahta.
Idk something on those lines maybe. Instead of trying to be a mard, and fight, maybe showing up as a gentleman might work?