Yosuga no Sora (by far the most popular Sphere work) only barely got an English translation after 10 years of work, in 2020. Imouto no Katachi is highly unlikely to be translated. Since there is no associated anime, or... really any info about it in the West, the Western fanbase is basically non-existent. I'm deeply involved in the YnS community, and other than myself, you might be the only person I've met who even knows it exists.. There simply is no fanbase. Yosuga no Sora gets all the attention, because it is has much higher production value. An MTL is possible, but even that's unlikely.