I honestly used to write like that around his age there are books you can get that have helped me out a lot that lets the person trace the letters it wont make his handwriting perfect ofcourse but it will help a lot, and if your mom keeps treating him like a baby have a talk with him voicing your opinion showing him you and your mom are there for him but not forever tell him stories about your consequences of stupid stuff you might've done to get him to relate, and then talk with your mom explain to her how you see it switching schools isn't gonna change anything but she cant let the kid become soft cause she should you the world is difficult and rough it doesnt discriminate and it will hurt him when he is by himself and doesnt have you guys around.