That sucks! Thankfully my parents were never married. But my grandfather and grandmother went thru a divorce when I was a lil kid. Then my younger brother got married and divorced within a year and a half. I'd hate to be a young kid going thru that. But I'm glad to see you pulled thru Things are starting to fall in the right place for you.
Although that news is typically not an easy thing for a teenager (nor anyone, really) to deal with, here's a thought to consider: how does your younger brother view your parents' relationship? By the time I was 14, I understood that my mother had little to no love in her heart for my father and I was sincerely hoping they would go their separate ways. Twelve years later, they're still married (for medical reasons more than anything) and still miserable and I still would rather see them live their lives apart from one another. That doesn't mean I don't love both of them dearly, but rather that my love for them includes a desire to see them happy. Maybe you can help your brother see the end of your parents' relationship in the same light.
That part does suck, for sure. It's never easy for anyone, at any age. The only thing is if your lil bro has had to deal with alcolism and stuff like that, it might be a relief somewhat. Living with someone who does the alcohol thing is traumatic at best, usually. Hopefully he'll understand why it had to happen, and in time he'll adapt, as will they.