What is the ruling on laughing upon hearing the news of someone's death in an accident while he was watching a match, and is it more appropriate to show mercy, grieve, and accept Allah's decree and destiny?

There is no doubt that ridiculing Muslims is forbidden, especially if they are deceased, as their right is even more emphasized. Allah Almighty says: (O you who have believed, let not a people ridicule [another] people; perhaps they may be better than them; nor let women ridicule [other] women; perhaps they may be better than them. And do not insult one another and do not call each other by [offensive] nicknames. Wretched is the name of disobedience after [one's] faith) [Al-Hujurat:11]. Therefore, it is not permissible to ridicule a Muslim for dying in a specific manner; rather, one should pray for mercy and forgiveness for them.