It's very unlikely. Jumping from such a great height of 11 stories is extremely dangerous. The impact on the body upon hitting the ground would be tremendous, causing severe internal and external injuries that are often fatal.
One possible reason could be mental distress. He might be suffering from depression or some other psychological disorder that made him feel hopeless. Maybe he had financial problems, lost his job, or had relationship issues.
Well, it depends on the context of the fanfic. If he jumps, he could be in a situation where he believes it's the only way to escape a powerful dark force on the tower. However, his Gryffindor courage might also lead to an unexpected rescue. For example, a phoenix could swoop in and carry him to safety at the last moment.
I'm sorry but without more information, it's hard to say if she's okay. Jumping from the 3rd story is extremely dangerous and could lead to serious injury or even death.
One exciting halo jump in a school story could be when a student overcomes their fear of heights during a skydiving event organized by the school's adventure club. They jump out of the plane and experience the rush of freefalling before the parachute opens.
One possible plotline could be Harry's reasons for jumping. Maybe he's under the influence of a dark spell and jumps to break free from it. Another could be that he jumps as a sacrifice to save his friends, believing it's the only way.
It could also be due to personal issues at home such as family problems, like parental conflicts or problems with siblings. These issues might have built up over time and led her to this desperate act. Another factor could be mental health problems that were not addressed. Depression or anxiety can often make a person feel so hopeless that they consider taking their own life.
There could be many reasons. Maybe he was facing extreme depression or mental health issues. Financial problems, relationship troubles, or a sense of hopelessness in life might have driven him to this extreme step.
The outcome could be catastrophic. You might break bones, suffer internal injuries, and there's a high chance of permanent disability or losing your life. Also, it could cause a lot of trauma for witnesses.
There could also be a story where the boys learned that their dad always wanted to learn a new hobby like painting. So they set up a little art corner for him in the house as their 'helpful jump'. They bought some basic art supplies and even signed him up for an online beginner's art class.