The title says it all. . .
Judd
If you want us to take your question literally, then the answer is no. While Columiba Law (or Med or Business, etc) may help slightly in admissions. the Columbia definition of legacy (which will give you more of an advantage) is the child of a graduate of Columbia College or Columbia Engineering.
http://undergrad.admissions.columbia.edu/ask/faq/question/2412
would one be regarded as legacy for having elder sibling in/through the Columbia College?
No. As I said above, Columbia only considers children of Columbia College or Columbia Engineering graduates as legacy.
OP, when you want a college, it helps to truly research their web sites, what they say and show. As ski pointed out for you, legacy is covered there. And you’ll need to know much more, to understand your match, if there is one, and how to present yourself best.
After speaking with a former admissions officer:
Having family members of graduate programs and/or family members working for or attending graduate departments will give a minor advantage relative to a parent or sibling working in or attending Columbia Undergrad.
That makes sense - on par as a small hook of demonstrated interest.