As a Cursed Spirit, I'm Obsessed with Raising My Little Brother

Everything that doesn't fit is my own invention. Lin Fengling doesn't know how she came to this world. Unlike the peaceful, tranquil life in the depths of her memories, danger hangs over every corner here, and scenes straight out of a TV drama play out before her eyes. Luckily, she seems to be a ghost: no one can see or hurt her. That is, until she meets a boy with orange-red hair and a pleasant scent. He asks, "What are you doing?" His words break her out of her state of drifting beyond the world and forge a connection between her and this unfamiliar place. The less-serious blurb Lin Fengling is a wandering spirit from another world. When she has nowhere to go, a boy takes her in. Then one day, Lin Fengling holds up a ball of meat and tells the boy, "This is my little brother." The boy is horrified and shouts, "You've finally gone crazy!" "I haven't." "That's just a ball of dough! It doesn't even look like you!" the boy pleads, trying to talk sense into her. Lin Fengling firmly believes it's her little brother. "He'll be fine once we raise him." After failing to persuade her, the boy gives up. Next time... "This is my little brother." "He looks human. He's a different species from you, isn't he?" The boy points at a kid with a sea-urchin hairstyle, suspicious that she might have stolen him from somewhere. "It's fine. I found this one too." "..." Not believable at all. Note: The female protagonist is invisible to others early on, and only gets a physical body later. Her little brother will appear later in the story. The plot goes wherever the inspiration takes me (who knows?), but the ending is already decided.