How do I force my father to quit alcohol?

I am a 21M who lost my mother to COVID a few years ago. Lately, I’ve been struggling with insecurity and uncertainty about my future. I’m preparing for competitive exams, but studying has become difficult because my father drinks every night, starting two hours before bed. Watching him drink daily has severely affected my mental health. I constantly fear losing him too, even before I’ve built my life, and this fear keeps me awake until 4 a.m. most nights. I’ve tried everything to make him stop—pleading, shouting, even breaking down—but nothing has worked. It feels like he doesn’t care about the impact his drinking has on me or our future. I can’t stop overthinking about what would happen if something happens to him—how we’d manage financially, especially for treatment costs. This fear has become inescapable, and I’m losing hope that he’ll ever quit, even for a single day. So how do I ask him or eventually force him to quit drinking for Atleast a period of time since I have to give competitive exams and I’m planning to escape this trauma and do better in life. Why and how does he just not care about me and my future but love his drink more than my mental health which has gone into complete vein?