Can you offer advice on my situation with my younger brother?

My brother is 23 and I just turned 27 (we both have no kids and not married), try my best to make this short, if you could please bear with me. He is been in what I would say is abusive relationship with his girlfriend/fiance. Got bad enough (recently) where he packed his bit of stuff and went back to FL. Not even a month or so later she buys him a plane ticket and convinces him to move back. I was blown away I thought this was the end of that shit for him.

I’ve done told him just about everything I think about his situation when he vents to me that he needs to leave her for good about how he hates things, anxiety, stress etc. I offered him to move with me several times and now he seems to be finally taking me up on my offer.

However, he admits he still smokes weed – that doesn’t bother me but it is his priority to go a state where it is legal. He says weed helps with his anxiety and I suspect depression, though he didn’t say it. He also admitted to me that he is flat out co-dependent not sure what that entails. He has always worked so that’s at least not an issue but he just doesn’t seem capable of moving forward in life. Also mentioned he is worried what might happen with her (shes told some nasty lies) or that he might do something. I don’t know if he was eluding to suicide or what.

This is where first problem starts I am ready to move anywhere there is an opportunity. My brother is dead set on certain states and I am also worried I am may not be able to handle him or help him. I certainly don’t want him to become overly dependent on me.

Why the hell he went back to her I have no idea. I guess people become addicted to abusive and toxic relationships. Some of the things he has told me in past is a flat out no-go, automatic break up and not getting back together type shit (for me least) so why he continues anything with his girlfriend/fiance is beyond me.

A final note I’ve grown up with family that had or still has drug and alcohol addictions and what not, and finally moving past all that emotional baggage myself. I do not want to put the brakes on my own life anymore for other people, even more specifically although painful with my own family especially when they don’t care about themselves.

Doesn’t leave me with much options do I essentially turn back on my brother and hope for best? Or do my best to take him under my wing without babying him and hope for the best?