Well, at first, they might be in denial about being brothers. Draco, with his pure - blood pride, and Harry, who has his own set of values. However, they could start to see similarities in each other. Draco might notice Harry's courage and Harry could see Draco's loyalty to his family (even if it's a different kind of family now). They could end up teaming up to solve mysteries within Hogwarts, and in the process, their relationship could transform from reluctant acceptance to a real, deep brotherly bond.
Inosuke survives throughout the manga. The story doesn't have his death as part of the plot. His character remains active and plays a significant role until the end.
First, you need to understand Inosuke's character really well. Know his strengths like his amazing physical abilities and his weaknesses like his lack of social graces. Then, choose the world you want to cross him over with. For example, if it's a fantasy world, figure out how his abilities would work there.