Welcome, Kimmilynn, I'm sorry for your sadness but glad you found us.
Your brother is young, hopefully he will face the reality of what he did and the consequences involved. Rehab is a good place to begin, it's not a hiding place, it's a place where he can learn to leave the drugs behind and face life on life's terms. I pray he will embrace this opportunity to turn his life around right now.
Some learn quickly and grab on to recovery as a life line, others take years and years and may go in and out of the revolving door of recovery/relapse. There is hope for your brother, he has youth in his side, but this is something he is going to have to do by himself for himself.
It was good of you to drive him to rehab, that's helpfully supporting actions he put in place for recovery. Now it may be best to step back and let him find his own way. If talking to him doesn't disturb you, then continue to talk to him and encourage him (gently and without expectations). But please don't become enmessed in his addiction, arguing with him or doing for him what he should be doing for himself or advocating for him with those he has wronged...this is all his to do.
Meetings help many of us find our balance when a loved one is self-destructing. Al-anon, Nar-anon and CoDA are three similar fellowships that teach us how to take very good care of ourselves...regardless of how our loved on is doing. Maybe give them a try and see if they don't help you too.
Take a read around, especially the sticky posts at the top of this forum, there is a lot of helpful information that may assist you in understanding what this is all about.
Hugs