At first I learnt いなくなる as the polite version of 死んだ/死んでいる, then I realised it could also be used as a negative version of いる to indicate state of existing/being in a place. Then how do you potentially avoid having, E.g., "if 〇〇 is not around, then what would you do" vs "if 〇〇 is dead, then what would you do" confused?
It is nakunatta((亡くなった)) that means died....not inakunatta((いなくなった)). That is a polite way to say "he died"....かれは亡くなりました (nakunarimashita).
1....if your husband was not around, then what would you do? 。。。いなかったら
2....if your husband died, then what would you do?。。。なくなったら