Mr Basil has answered this correctly. Context set by previous sentence is important to understand the meaning of "Yeh bhi koi jeena hai" and "Yeh bhi koi marna". Great song btw, if you ask me!

Although my Hindi is totally lousy:--- Yaara seeli seeli birha ki raat ka jalna Friend, slowly slowly the night of separation burns Yeh bhi koi jeena hai, yeh bhi koi jeena hai Is this called living, is this called living? Yeh bhi koi marna Is this called dying? Ref:- http://www.hindilyrics.net/translation-Lekin/Yaara-Seeli-Seeli.html I'd take it to mean "Some people have to live (through this night), some have to die" but that's just me. In this context I see (koi = koi log = some people)

next time you will post the entire song ,