The slayer with monophobia

Tanjiro used to be a happy boy until his family was killed by a demon and he started on his path to become a demon slayer, luckily most of his happiness remained and his smile could literally outshine the sun. But that changed when Muzan kidnapped him one night. Muzan did horrible things to Tanjiro and even though he was rescued by the hashiras, the things that Muzan did to him never left him. Tanjiro merely became a shell of his former self, he flinches at every small noise or movement and when his eyes aren't full of fear, they are dull. Tanjiro hasn't smiled since he was rescued and he has developed monophobia meaning he is scared to be alone. He always has to have a hashira with him, he can't even be alone in one room for merely a few minutes because he gets too scared and has a panic attack. Can the hashira's restore Tanjiro to his happiness? Or his he forever stuck as a scared, timid boy?

Warning: this story contains mentions of physical abuse, emotional abuse, sexual abuse and rape. Read at your own risk.