you were a human with asthma, really bad asthma due to your bad luck. You couldn't be a demon slayer so you became a kakushi. While on a mission to go help some slayers, you started having an asthma attack and were left behinde. Aizetsu found you and helped you somehow he felt bad for you after learning about your problem. So what did he do? He kidnapped you and held you in a house away from work and effort and around nature for more pure air

"Are flowers okay for you? "

he asked curious.