Should I stay or just leave?

I can understand where your mums coming from but its not only ruining her lives that your brothers drink and arent really living life to its best at the moment, but its ruining yours aswell your son shouldnt be in that environment and i think you should move out, just be truthful to your mum as you already have done and find a house you could even look quite near by for a house? because then you could still help your mum out now and again just a thought but deffo move out!