Basically Kabu is saying that if he dies, Nirasawa has permission to kill himself, but Kabu also clarifies that he doesn't plan on letting Nirasawa die.
Basically Kabu is saying that if he dies, Nirasawa has permission to kill himself, but Kabu also clarifies that he doesn't plan on letting Nirasawa die. baebri97
http://www.mangago.zone/read-manga/bi_no_kyoujin_smoke/nmt/c004/7/