Is 老鸽 (lit. "old pigeon") slang?
老鸽 is an intentional typo.  鸽(Pigeon) can mean "get stood up"(被鸽了，被放鸽子) or "stood sb. up"（放某人鸽子）.  So this is the combination of both 'bro' and 'a guy that often does not show up in appointments'.