You may be able to file the I-130 while living abroad, but will need to live in the United States when your brother applies for the immigrant visa--once his priority date becomes current. At present, it takes many years for a petition for a sibling to become current, so it may make sense so file the petition now and see where you live when it becomes current. You should consult an experience immigration attorney to discuss the specifics of your case in detail.
I agree with my colleague you can file an I-130 petition while living abroad; however its 4th preference category which will be a long wait.
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The domicile requirement will not become an issue in the case until the priority date is current which is likely 12-15 years away. You can worry about the requirement then. At this point, I'd file the I-130 and get the clock ticking. You can reevaluate the law when his priority date is current. Restablishing domicile isn't that difficult.