There could be many reasons behind such a tragic event. Maybe there was a misunderstanding, or some underlying family issues. However, without more information, it's hard to tell the exact full story. It's a very sad situation and proper investigations should be carried out to find out the truth.
One possible reason could be that the grandfather didn't approve of the child's therian identity and there was a conflict that escalated. Another could be an accidental shooting, like if the grandfather was handling a gun carelessly around the child.
Often, Kid Goku is portrayed as the carefree and adventurous type. He's always looking for the next exciting thing to do, whether it's chasing after a strange animal or exploring a new area. He might be a bit naive in some aspects, especially when it comes to things like emotions.
Once upon a time, there was a kid named Tim in school. He was a bit different, wearing thick glasses and being really into books. Some of the popular kids in the class started to bully him. They would knock his books out of his hands in the hallway and call him names like 'nerd' and 'four - eyes'. Tim was really sad but he didn't tell anyone at first. One day, a new teacher noticed what was going on. She started to keep a closer eye on those bullies and also encouraged Tim to be proud of who he was. Eventually, with the teacher's help, the bullying stopped and Tim became more confident.
One popular storyline could be their adventures together in the mountains. They might encounter strange creatures and have to use their wits and skills to overcome difficulties. For example, they could find a lost magical item and have to return it to its rightful place.