It's understandable that your grandfather may feel concerned about your interests in shooting games, weapons, and war, especially if they seem intense or frequent. Video games and discussions surrounding them can sometimes evoke thoughts about violence or conflict, which might lead to worries about mental health or well-being.
It might help to consider why you're drawn to those topics. Many people enjoy shooting games and similar genres for the strategy, teamwork, or even the storytelling involved. They can also be a way to explore complex themes in a safe environment.
You could try talking to your grandfather about your interests, explaining what you enjoy about these games, and reassuring him that your enthusiasm doesn't reflect a fixation on death. Additionally, you might want to balance your interests with other hobbies or discussions to show a broader range of engagement in life. Communication can go a long way in addressing his concerns and fostering understanding.